docs(decisions): restructure into pql governance DQR tree

Phase 1 of the pql migration. Moves the flat decisions/*.md layout into
governance/{decisions,questions,rejected}/<domain>.md — the tree pql's
`decisions sync` parses natively (record type from subdir, domain from
filename stem). Proven against pql 1.6.2: sync reports 357 records
(237 D / 108 Q / 12 R), 1057 refs, broken: 0; validate ok.

- 6 D-domain files -> governance/decisions/ (git renames)
- 5 questions-<domain>.md -> governance/questions/<domain>.md (prefix dropped)
- rejected.md split by domain -> governance/rejected/{architecture(R-001..010),
  economics(R-011),perception(R-012)}.md
- decisions/README.md + questions.md index folded into governance/README.md;
  pql's `decisions sync` now auto-maintains the record index appended below
  the hand-written domain guidance (no more manual ID-list table upkeep).
- .pql/config.yaml: canonical vault config (tracked, not ignored).

Link rewrites are token-preserving: only the relative `foo.md` path portion
changes (e.g. `rejected.md#r-011` -> `../rejected/economics.md#r-011`); every
`[D-NNN]` bracket text and `#anchor` stays byte-identical, so pql's reference
extraction is unaffected. The one-shot transform is committed at
tooling/pql-migrate/restructure_decisions.py for provenance.

Codebase path references to decisions/ (CLAUDE.md, rules, skills, docs) are
updated in a follow-up commit.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

governance/rejected/architecture.md

@@ -0,0 +1,43 @@
+# Rejected Alternatives — Architecture
+
+Rejected proposals in the **architecture** domain, rationale preserved for the audit trail.
+
+### R-001: Stellaris mod
+- **Rejected:** 2026-02-08
+- **Reason:** Character system too shallow, multi-empire assumption conflicts with the Settled Reach's single-civilization focus, wormhole-as-infrastructure not achievable within Stellaris modding. Team Leader's experience with Star Trek: New Horizons confirmed that even well-suited IPs struggle with character connection in Stellaris.
+
+### R-002: CK3 total conversion
+- **Rejected:** 2026-02-08
+- **Reason:** Would require building a space map from scratch within CK3's framework - essentially building a game inside a game. The map system fundamentally doesn't support the complexity needed.
+
+### R-003: Other existing games (Distant Worlds 2, GalCiv IV, Sins of a Solar Empire II, Victoria 3)
+- **Rejected:** 2026-02-08
+- **Reason:** Each captures at most 40% of what's needed. Smaller modding communities, less mature tools, and none solve the core CK3+Stellaris hybrid requirement.
+
+### R-004: Pure Bevy (Rust) — no Godot
+- **Rejected:** 2026-02-09
+- **Reason:** No visual editor (level design is code-only). UI framework in flux. API breaks significantly between versions. For a solo developer who needs visual tools for hand-crafted buildings ([D-014](../decisions/scope.md#d-014-v01-map-specification)), Godot's editor is a massive productivity advantage. Bevy's ECS is used — just not its renderer.
+
+### R-005: Pure Godot (GDScript or C#)
+- **Rejected:** 2026-02-09
+- **Reason:** Scene tree paradigm fights ECS-style simulation. Perception queries ([D-017](../decisions/perception.md#d-017-perception-modes-as-character-build-system)) and information boundaries ([D-010](../decisions/architecture.md#d-010-multiplayer-ready-architectural-baseline)) map naturally to ECS component queries, not scene tree traversal. Multi-core scaling for expanded content impossible in GDScript. Kept as kill-switch fallback if Rust architecture exceeds time budget.
+
+### R-006: Godot + Rust via GDExtension
+- **Rejected:** 2026-02-09
+- **Reason:** gdext is pre-1.0 with breaking API changes. Godot version upgrades break GDExtension ABI. Thread safety at FFI boundary is CRITICAL risk (`Gd<T>` is `!Send`/`!Sync`). Couples Rust and Godot learning curves. Subprocess/IPC achieves the same architecture without the FFI risk surface, and maps directly to [D-010](../decisions/architecture.md#d-010-multiplayer-ready-architectural-baseline) client-server. See `docs/architecture/risk-godot-rust-bridge.md` for full analysis.
+
+### R-007: Godot + C++ via GDExtension
+- **Rejected:** 2026-02-09
+- **Reason:** More mature bindings than gdext, but trades Rust's safety guarantees for C++ memory unsafety. No advantage over subprocess/IPC approach. Developer not experienced in C++.
+
+### R-008: Fyrox (pure Rust engine)
+- **Rejected:** 2026-02-09
+- **Reason:** Single maintainer. ~1/50th of Godot's community. Less documentation, fewer tutorials, weaker AI training data for Claude Code. Single-maintainer risk unacceptable for multi-year project.
+
+### R-009: Custom framework (Rust + raylib/macroquad)
+- **Rejected:** 2026-02-09
+- **Reason:** Maximum control but you build everything — tilemap rendering, camera, UI, audio, input, asset pipeline. Months before testing a mechanic. The game's hard problems are simulation, not rendering — don't reinvent the rendering wheel.
+
+### R-010: protobuf for client-server serialization
+- **Rejected:** 2026-02-09
+- **Reason:** Schema evolution across independent deployments is a problem we don't have (one developer, client and server ship together). Poor GDScript support. Rigid schema fights dynamic HUD composition driven by perception modes ([D-017](../decisions/perception.md#d-017-perception-modes-as-character-build-system)). MessagePack's schema-optional nature fits better.

governance/rejected/economics.md

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+# Rejected Alternatives — Economics
+
+Rejected proposals in the **economics** domain, rationale preserved for the audit trail.
+
+### R-011: Single currency for Phase 2 economics
+- **Rejected:** 2026-04-05
+- **Proposed by:** Burnelli-Sheldon (economist), Sprint 32 Workshop #796 Round 1
+- **Proposal:** Use a single currency for the Phase 2 economics simulation to reduce model complexity; exchange-rate mechanics could be added in a later phase.
+- **Reason:** Three currencies create structural economic bloc tension as an emergent property of initialization, requiring no event generation. The Tractus/Mark divide maps directly to the canonical Assembly vs. Compact political divide. Deferring to a later phase would require retrofitting political geography into a running simulation. Complexity cost low; design value high.
+- **Raised by:** Lead directive overruling the recommendation.
+- **Cross-reference:** [D-171 (economics.md)](../decisions/economics.md#d-171-three-currency-system)
+- **Note:** Canonical location is `rejected.md`. Two duplicate copies in `economics.md` were removed 2026-06-06 (id-collision cleanup).

governance/rejected/perception.md

@@ -0,0 +1,8 @@
+# Rejected Alternatives — Perception
+
+Rejected proposals in the **perception** domain, rationale preserved for the audit trail.
+
+### R-012: Overheard NPC conversation system (D-078) — scrapped
+- **Rejected:** 2026-04-10
+- **Reason:** The entire NPC ambient interaction model (overheard conversations, room grammar, zone-type NPC population, behavior engine for physical spaces) is scrapped. These systems were designed speculatively before a walkable environment exists. The NPC interaction model will be designed and built from scratch after Phase 5 (world generation at tile level) is complete. All content authored against these systems (overheard.ron, zone-type conversation pools) is orphaned. Related content pattern note in content.md and D-078 in perception.md are superseded.
+- **Cross-reference:** D-078 (perception.md), content pattern note (content.md #664)