docs(decisions): add D-085 per-game save dirs, Q-029 save file format

D-085: per-game save directory structure with F5/F6 quicksave/quickload.
Q-029: open question tracking long-term save file format design.

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

decisions/README.md

@@ -10,12 +10,12 @@ Cross-domain decisions live in one file with cross-reference notes in related fi
 
 | File | Domain | Decisions |
 |------|--------|-----------|
-| [architecture.md](architecture.md) | Technical foundation | D-008, D-009, D-010, D-012, D-020, D-026, D-030, D-031, D-041, D-042, D-054, D-055, D-066, D-068, D-073 |
+| [architecture.md](architecture.md) | Technical foundation | D-008, D-009, D-010, D-012, D-020, D-026, D-030, D-031, D-041, D-042, D-054, D-055, D-066, D-068, D-073, D-085 |
 | [perception.md](perception.md) | Player observation | D-011, D-015, D-016, D-017, D-018, D-019, D-033, D-035, D-043, D-044, D-045, D-046, D-047, D-048, D-049, D-052, D-056, D-057, D-058, D-059, D-060, D-061, D-067, D-069, D-070, D-071, D-072, D-076, D-077, D-078 |
 | [content.md](content.md) | NPC, dialogue, templates | D-023, D-024, D-025, D-028, D-029, D-032, D-034, D-035, D-036, D-037, D-050, D-062, D-063, D-064, D-074, D-075, D-084 |
 | [scope.md](scope.md) | Game concept, prototype | D-001, D-003, D-005, D-006, D-007, D-013, D-014, D-027, D-038, D-039, D-051, D-053, D-065 |
 | [process.md](process.md) | Team, workflow | D-004, D-021, D-022, D-040 |
-| [questions.md](questions.md) | Open questions | Q-001 through Q-028 |
+| [questions.md](questions.md) | Open questions | Q-001 through Q-029 |
 | [rejected.md](rejected.md) | Rejected alternatives | R-001 through R-010 |
 
 ## Querying Decisions

decisions/architecture.md

@@ -210,4 +210,19 @@ Technical foundation decisions that constrain implementation: engine, client-ser
 
 ---
 
-*16 decisions. Last updated: 2026-02-16*
+### D-085: Per-game save directory structure
+- **Date:** 2026-02-25
+- **Decision:** Every new game creates a dedicated directory under the user save path. All saves for that game (manual, quicksave, autosave) live inside the game's directory. Directory name includes a human-readable game identifier and creation timestamp.
+- **Rationale:** Natively groups saves by game without requiring a database or index file. Players can browse, back up, or delete game saves at the filesystem level. Avoids a flat save folder where 50+ files from different games are interleaved.
+- **Structure:** `user://saves/<game-id>/` where `<game-id>` is `<timestamp>-<seed>` (e.g., `20260225-143022-a7b3f1/`). Inside: `quicksave.sav`, `autosave.sav`, `manual_001.sav`, etc.
+- **Constraints:**
+  - Game directory created on "New Game" — even before the first save, so the path exists for quicksave/autosave.
+  - F5 = quicksave (overwrites `quicksave.sav` in the active game dir).
+  - F6 = quickload (loads `quicksave.sav` from the active game dir).
+  - Loading screen lists game directories sorted by last-modified, shows most recent save per game.
+- **Raised by:** Team Leader (Jeroen)
+- **Dissent:** None
+
+---
+
+*17 decisions. Last updated: 2026-02-25*

decisions/questions.md

@@ -168,6 +168,20 @@ Tracked questions awaiting discussion or resolution.
 - **Assigned to:** Gestalt, Tyre
 - **Source:** Sprint 16 PR #59 review discussion (2026-02-23)
 
+### Q-029: Save file format design
+- **Status:** Open
+- **Question:** What should the long-term save file format look like? Key considerations:
+  1. **Versioning and migration:** How do saves survive across game versions? Schema evolution strategy (field additions, renames, removals). Should saves embed a version number and run migrations on load?
+  2. **Compression:** Raw MessagePack vs compressed (zstd, lz4)? Tradeoff between save/load speed and file size. SaveStateV1 is already MessagePack — does that carry forward?
+  3. **Integrity:** Checksums or signatures to detect corruption? CRC32 header?
+  4. **Metadata header:** Should the file have a readable header (game version, save date, play time, character name) that the loading screen can read without deserializing the full save?
+  5. **Determinism:** D-010 requires deterministic simulation. Can saves capture enough state to resume deterministically, or is approximate resume acceptable?
+  6. **Modding:** Should the format be documented for mod authors? Does it need extension points?
+  7. **Cloud sync:** Any considerations for Steam Cloud or similar? File size limits?
+- **Context:** Sprint 19 implements a quick-and-dirty save format (D-085 per-game directories, MessagePack serialization from SaveStateV1). This question tracks the thorough design pass for production quality.
+- **Assigned to:** Tyre, Dudley
+- **Source:** Team Leader directive (Sprint 19 planning)
+
 ---
 
-*28 questions (7 resolved, 1 partially resolved, 20 open). Last updated: 2026-02-25 (Q-028 resolved → D-084)*
+*29 questions (7 resolved, 1 partially resolved, 21 open). Last updated: 2026-02-25 (Q-029 added)*