docs(docs): file D-096–D-109 and Q-045–Q-050 from generator workshop

14 confirmed decisions filed across architecture.md (10) and content.md (4).
6 open questions filed in questions.md (Q-046 resolved immediately by D-108).
README.md index updated.

Key decisions: DistrictLayoutMode (D-096), guarantee tier system (D-097),
MobileChunk spec (D-108), DamageOverlay prohibition (D-109), WorldTier
enum with corrected constraint ceilings, heritage grammar overlay (D-104).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

decisions/architecture.md

@@ -245,4 +245,95 @@ Technical foundation decisions that constrain implementation: engine, client-ser
 
 ---
 
-*19 decisions. Last updated: 2026-02-25 (D-094 added — Station District Layout Workshop, Sprint 20)*
+### D-096: DistrictLayoutMode — Grid and Organic Support
+- **Date:** 2026-02-27
+- **Decision:** Two layout modes coexist for district generation. `Grid`: Commission-planned districts with rectilinear block placement. `Organic`: pioneer/growth districts with block offsets (±16 sim tiles per axis), rotation (0–3 steps, 15° increments), variable street width (0.75–2.0×). Hard technical ceiling: maximum rotation ±45°. Beyond 45°, tile-based pathfinding produces unacceptable movement artifacts. Organic districts produce curved-street impressions through angular jogs and irregular setbacks. Grid vs. Organic proportions must vary per seed to prevent predictable meta-level patterns.
+- **Rationale:** Grid = power imposed (Commission-planned). Organic = power negotiated (pioneer settlements, organic growth). Both modes encode political and settlement history in spatial form.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. Full spec: `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-1.
+- **Raised by:** Tyre (technical architecture), Miri (cultural grammar). Full team sign-off.
+- **Dissent:** None.
+- **Cross-reference:** D-094 (spatial hierarchy), Q-036 (district generator)
+
+### D-097: Guarantee Tier System — Universal / Full-Only / Conditional
+- **Date:** 2026-02-27
+- **Decision:** The district generator runs a `GuaranteeAuditResult` with three tiers of spatial guarantees. **Tier 1 — Universal (all inhabited):** Social Hub, Informal Zone, Encounter Corridor. **Tier 2 — Full-complexity:** Traffic Chokepoint, Institutional Space, Insider Space, Economic Node, Horizon View Corridor (coastal), BreachOnly Zone (≥1), Rooftop Discovery Zone (tall structures). **Tier 3 — Conditional:** A-1 Elevated Vantage, A-2 Egress Multiplicity, A-3 Temporal Opacity Window, A-4 Non-Institutional Route, Economic Asymmetry Signal, Power Gradient Visibility. A Full-complexity coastal urban hub gets up to 13 checks. Archetype placement must vary in angular position (not just distance) across seeds — audit fails if archetypes cluster predictably across a test batch of N seeds.
+- **Rationale:** The generator makes contracts it keeps. Guaranteed affordances ensure every playstyle has spatial affordances in any district, without hand-crafting each location.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. Full spec: `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-2.
+- **Raised by:** Gestalt (tier structure + assassin lens integration), Tyre (GuaranteeAuditResult struct). Full team sign-off.
+- **Dissent:** None.
+- **Cross-reference:** D-103 (assassin lens guarantees A-1 through A-4), D-102 (horizon view corridor — Tier 2 coastal)
+
+### D-099: WallBackside / TileBehindState — Dual Classification
+- **Date:** 2026-02-27
+- **Decision:** Two complementary enums classify tiles behind wall surfaces. `WallBackside` (structural): what is physically there — `AdjacentSpace | StructuralFill | ServiceVoid | ChunkBoundary | Exterior`. `TileBehindState` (gameplay): what kind of space this represents — `StructuralFill | HiddenRoom | Interstitial`. Mapping: `ServiceVoid → Interstitial`; `AdjacentSpace → HiddenRoom or StructuralFill` depending on access tier. Era-tagged infrastructure cavity contents with standardized color codes: Era 1 power conduit only (`#c8b840`), Era 2 power + water/coolant (`#4888c8`) + comm lines (`#b8b8b8`), Era 3 full bundle. Backside assignments within a template must have seed-driven variation — not fixed template values.
+- **Rationale:** "Every wall is a secret keeper." No tile is ever void. Dual classification separates structural truth (what's there physically) from gameplay meaning (what does this imply for the player's investigation).
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-4.
+- **Raised by:** Tyre (WallBackside), Gestalt (TileBehindState). Full team sign-off.
+- **Dissent:** None.
+
+### D-100: Dynamic Modification via Overlay — DamageOverlay and RegenerationStrategy
+- **Date:** 2026-02-27
+- **Decision:** Generator output is immutable after Phase 1. All post-generation modifications are applied via overlay, not re-generation. `DamageOverlay` struct: `overlay_type` (GasExplosion | Fire | Structural { collapse_direction } | Flooding), `epicenter: ChunkLocalPos`, `radius: f32`, `intensity: f32`, `scatter_seed: u64` (variation within zone only). `RegenerationStrategy` enum: `LocalOverlay(DamageParameters)` for in-playthrough events (MANDATORY), `SoftReseed { seed_modifier: u64 }` at scenario boundaries only, `FullReseed` at era-level discontinuities only. Trauma event → visual stage mapping: PhysicalDestruction/ViolenceEvent → Stage 2 (Fresh Aftermath), decays to Stage 3; EconomicDisruption/PoliticalShock/MigrationShock → quarter fill modifier. Full stage sequence: Stage 1 Active → Stage 2 Fresh Aftermath → Stage 3 Stabilized → Stage 4 Reconstruction → Stage 5 Healed Scar. Destruction palette is corruption-only: no new colors introduced by destruction. Single exception: `#c8d8f0` open-sky tile appears when a roofed structure has its roof removed. See D-109 for the XOR prohibition as architectural mandate.
+- **Rationale:** Modification history diverges per playthrough on the same seed. Same world, different event histories, different delta layers — this is the replayability engine. Causal legibility requires the player to be able to read what happened from the world state.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-5.
+- **Raised by:** Tyre (structs), Gestalt (LocalOverlay mandate). Destruction stages and palette constraint: Araminta (Round 5).
+- **Dissent:** None.
+- **Cross-reference:** D-109 (XOR prohibition as architectural mandate), D-107 (trauma events — cultural track)
+
+### D-101: ZonePalette Modifier System
+- **Date:** 2026-02-27
+- **Decision:** Zone palettes use `ZonePalette { base: BasePalette, modifiers: Vec<PaletteModifier> }`. Eight canonical base terrain types: T1 temperate farmland (warm organic, natural lighting) / T2 industrial farmland (cool grey-green, artificial lighting) / T3 wilderness / T4 grassland / T5 coastal water (deep near-black blue, animated specular; referenced by D-102 horizon corridor guarantee) / T6 beach/coastal margin (warm dark tan) / T7 mountain/high terrain (dark blue-grey stone, snow at elevation) / T8 desert/arid. T1 and T2 are explicitly distinct farmland types. Additional terrain types must be specified with new numbers — not silent replacements for existing types. Modifier axes: A (heritage root → material character), B (economic tier → condition/density), C (era → material generation), plus faction overlay, climate, condition, season. Palette modifiers influence NPC appearance as well as environment (people dress like they're from here).
+- **Rationale:** A zone's visual identity must be legible at a glance. Palette modifiers create cultural visual identity without rewriting base terrain.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-6.
+- **Raised by:** Araminta (terrain types and color specs, canonical T5/T7 numbering corrected Round 5), Tyre (palette struct). Full team sign-off.
+- **Dissent:** None.
+- **Cross-reference:** D-102 (horizon view corridor — T5 coastal water is the referenced terrain type), D-104 (heritage grammar overlay — modifier axis A)
+
+### D-102: Horizon View Corridor as Coastal Guarantee
+- **Date:** 2026-02-27
+- **Decision:** A **negative-space** reservation for coastal districts: ≥8 visual tiles unobstructed view corridor from nearest public street to water's edge. No building, tree, or z=4 element may occupy this corridor. A low z=2 element (railing, bench, bollard) marks the waterfront point as a designed viewing location. Tier 2 Conditional guarantee — applies to Full-complexity coastal districts. Position within the district must vary per seed; the Wow Moment of seeing the horizon must be discovered, not expected.
+- **Rationale:** "Negative-space reservation" framing — the generator reserves space by prohibiting placement, not by placing something. The view of the horizon is a spatially guaranteed player experience.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-7.
+- **Raised by:** Araminta (visual grammar and negative-space framing), Tyre (implementation constraint). Full team sign-off.
+- **Dissent:** None.
+- **Cross-reference:** D-097 (guarantee tier system — Tier 2), D-101 (ZonePalette — T5 coastal water is the terrain type this guarantee references)
+
+### D-103: Assassin Lens Spatial Guarantees — A-1 through A-4
+- **Date:** 2026-02-27
+- **Decision:** Four derived spatial properties validated by the guarantee audit for Full-complexity districts. These are **derived properties of existing spatial configuration**, not assassin-tagged features — they add no generation cost; the audit validates existing output. **A-1 Elevated Vantage** (Tier 3): ≥1 position with clear LOS cone to Traffic Chokepoint. **A-2 Egress Multiplicity** (Tier 3): ≥2 exit routes to adjacent districts. **A-3 Temporal Opacity Window** (Tier 3): ≥1 time window where Social Hub has reduced ambient NPC coverage. **A-4 Non-Institutional Route** (mandatory Full-complexity): ≥1 route to any Insider zone not passing through high-security institutional spaces. A-1/A-2/A-3 are Tier 3 Conditional (trigger on `complexity_tier == Full`). A-4 is mandatory for all Full-complexity districts regardless of playstyle.
+- **Rationale:** The investigator/assassin playstyle needs guaranteed affordances without the generator explicitly building for assassination. Derived properties keep generation cost zero while ensuring spatial conditions exist.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-8.
+- **Raised by:** Gestalt (assassin lens framing and derived-properties insight). Full team sign-off.
+- **Dissent:** None.
+- **Cross-reference:** D-097 (guarantee tier system — Tier 3)
+
+### D-106: Vertical Scale Architecture and Rooftop Bar Clause
+- **Date:** 2026-02-27
+- **Decision:** Four height tiers: S1 (1–2 z-levels, surface + roof/mezzanine), S2 (3–10), S3 (11–30), S4 (30+). Shadow length is the primary height signal in top-down view (2–40 visual tiles). Lazy z-level loading: `ZLevelLoadState: Loaded | Skeleton | Ungenerated` — only current + adjacent z-levels filled by Phase 2. **Rooftop Bar Clause:** Every tall structure (z_band_count ≥ 3) must assign `RooftopConfig: Restricted | PublicWithHiddenLayer`. Discovery layer mandatory in both configurations. Heritage root **weights the probability** between the two configs — it does not determine the outcome. Final config is seeded per-building; a minority of buildings of any heritage root may be the non-dominant type (a Frost building with a rooftop bar must be possible). Z-band floor boundaries must have seed-variation within cultural ordering constraints. Vertical access routes are playthrough-history dependent.
+- **Rationale:** Height has meaning — floor 30 has information floor 1 cannot have because it is harder to reach. Full determination of rooftop config by heritage root kills the discovery moment.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-11.
+- **Raised by:** Tyre (z-level architecture), Ozzie (Rooftop Bar Clause — discovery guarantee). Ozzie + Araminta corrected "determines" → "weights probability" in Round 5.
+- **Dissent:** None.
+- **Cross-reference:** D-094 (spatial hierarchy), D-097 (guarantee tier system — Rooftop Discovery Zone is Tier 2)
+
+### D-108: MobileChunk Specification
+- **Date:** 2026-02-27
+- **Decision:** Entity-carried interior space attached to a mobile world entity. Not a district — uses the same chunk fill primitives in a simpler flat structure (no Phase 1/Phase 2 split, no block grid, no zone negotiation). Key structs: `MobileChunk`, `MobileInterior`, `VesselClass`, `MobileMovementState` (Docked / InTransit / InterSystem / Idle), `TransitSocialModifier`, `MobileNpcSlot`, `NpcPersistence` (Crew | Passenger). `Idle` = vessel parked at a location but not docked to infrastructure (anchored ship, grounded shuttle). Vessels are **persistent world entities** — interior cache keyed by entity_id persists across voyages for crew state. `Docked` state requires `dock_position`, `connected_chunk: Option<ChunkCoord>`, `docked_since: SimTick`, `scheduled_departure: Option<SimTick>`. `scheduled_departure` must be populated by the generator; vessels without departure schedules are an error state. Cultural grammar: `TransitSocialModifier` with `TransitVariant` (BoundedLinear | BoundedMobile | InterSystem). Vessel visual grammar (5 rules): (1) hull uses vessel-identity material, not zone palette; (2) windows reveal exterior context (docked vs. transit); (3) compression modifier tightens proportions; (4) section transitions use vessel-identity threshold elements; (5) class stratification via proportion, not palette. Replayability requirements R-V-1 through R-V-6 in `docs/workshops/generator-architecture/round-4-notes.md` §5. Memory: ~0.5–4KB metadata + up to 64KB ChunkData per vessel; paged by streaming model.
+- **Rationale:** "The journey is content — mobile environments are social pressure cookers, not loading screens with chairs." Vessel persistence and crew state continuity make the world feel real.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-13.
+- **Raised by:** Tyre (struct design), Miri (cultural grammar — `miri-round4.md`), Nigel (replayability requirements), Ozzie (player experience). Visual grammar: Araminta (`araminta-round4.md` §2).
+- **Dissent:** Nigel initially proposed instanced districts for vessels; lead ruled entity-carried MobileChunk for persistence.
+- **Cross-reference:** D-100 (DamageOverlay applies to vessel damage), D-109 (LocalOverlay mandate), Q-046 (departure schedule — resolved by this D-record)
+
+### D-109: DamageOverlay / RegenerationStrategy Prohibition — Architectural Mandate
+- **Date:** 2026-02-27
+- **Decision:** XOR reseeding for in-playthrough events is **architecturally prohibited**. `LocalOverlay` is the mandatory modification strategy for all events that occur while the player is present. `SoftReseed` and `FullReseed` are permitted only at scenario-boundary and era-level discontinuities respectively — events the player was not present for, where causal legibility is not required. This prohibition is filed as a separate D-record from D-100 because it establishes the modification principle for the entire game, not just the overlay mechanics.
+- **Rationale:** Causal legibility: the player must be able to look at a damaged district and understand what happened. XOR reseeding destroys the causal thread. Unanimous consensus across all workshop participants — the strongest architectural agreement of the entire workshop.
+- **Source:** Generator Architecture Workshop (#562), 2026-02-27. `docs/workshops/generator-architecture/workshop-outcomes.md` §D-READY-14.
+- **Raised by:** Gestalt (XOR prohibition framing), Tyre (RegenerationStrategy struct). Unanimous.
+- **Dissent:** None.
+- **Cross-reference:** D-100 (DamageOverlay + RegenerationStrategy full specification)
+
+---
+
+*29 decisions. Last updated: 2026-02-27 (D-096 through D-109 added — Generator Architecture Workshop #562)*