Lock wall-material decision: wood + stone, custom-authored

Wood walls (early game) custom-authored on top of FG_Houses warm-brown
timber palette to preserve the Stardew-cabin warmth that's the project's
aesthetic anchor. ~½ day of pixel art for corner/T/cap/cross variants.

Stone walls (upgrade material) imported from FG_Fortress autotile-solvable
as-is. Both materials plug into the same WallMaterial enum / construction
pipeline. Phase 5 estimate bumped from 2-3 wks to 2.5-3.5 wks.

Phase 1 wall-rendering test now specified: use FG_Fortress as the
drop-in test material; wood walls land in Phase 5 alongside the
authoring task.

Iconic Homestead $19.99 fallback formally not needed.

memory.md decisions table now includes the wall locks; the original
3-option open question collapsed to a back-reference. art.md got a
new 'Wall-material decision' section replacing the options block.

Wolf-sprite question still open; Ventilatore search dispatched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/implementation.md

@@ -66,7 +66,10 @@ The five items from `memory.md` *Open questions / Audit*. None of these need cod
 **Goal:** an 80×80 map with the locked camera UX. No pawns yet; just a navigable empty world.
 
 - [ ] `TileMap` with 6 layers per `architecture.md`: 0 Terrain · 1 Floor · 2 Wall · 3 Designation · 4 Roof · 5 Fog. Set z-indices, modulate, etc.
-- [ ] Tileset import: at least one terrain (grass) + one floor + one wall material from ElvGames bundle. Skip autotile for now if Phase 0.5 audit hasn't completed.
+- [ ] Tileset import (audit complete, so we can be specific):
+  - **Terrain (grass):** `Forest Tileset 4 Seasons/Tilesets/FG_Forest_Spring.png` (or `FG_Grounds.png` for cleaner ground).
+  - **Wall (test material):** `Fortress Tileset 2 Seasons/Tilesets/FG_Fortress.png` — autotile-solvable, drops in clean. Wood walls (custom-authored on FG_Houses) wait for Phase 5; Phase 1 doesn't need both materials, just *something* to render.
+  - **Floor:** placeholder from `FG_Grounds` or similar — final floor variants in Phase 5.
 - [ ] Generate an 80×80 placeholder map (procgen later — for now, a hand-painted test map saved as a `.tscn` is fine)
 - [ ] Tick loop: `Sim` runs at 20 Hz, render free-runs at 60 Hz, decoupled. Pawn-position lerping comes in Phase 2.
 - [ ] Speed control: 1× / Fast (5×) / Ultra (12×) / Pause. Buttons fixed top-bar. Per `architecture.md` table — sim-tick queue scales by speed factor.
@@ -134,14 +137,19 @@ The five items from `memory.md` *Open questions / Audit*. None of these need cod
 
 ---
 
-## Phase 5 — Building, walls, floors, containers (~2–3 weeks)
+## Phase 5 — Building, walls, floors, containers (~2.5–3.5 weeks; was ~2–3, bumped for wood-wall art authoring)
 
-**Goal:** the player can shape the world. End of phase: build a functional cabin.
+**Goal:** the player can shape the world. End of phase: build a functional wooden cabin, with stone fortress walls available as the upgrade material.
 
 - [ ] Designation paint mode (controller reused later by stockpile-paint, no-roof, etc.) — drag-paints ghosts on Layer 3, green-if-placeable / red-if-blocked
 - [ ] `BuildJob` queue on `World`, with material requirements
 - [ ] Construction WorkProvider: nearest-job-first, hauls materials → walks to ghost → works N ticks → swaps Layer 3 ghost for real Layer 2 wall (autotile fixes neighbours) → updates pathfinder
-- [ ] **Walls:** wood, stone (autotile per Phase 0.5 audit outcome — fall back to manually-painted variants if autotile pieces are missing)
+- [ ] **Walls — wood (locked-in via 2026-05-10 audit):**
+  - **Art:** author corner / T-junction / cap / cross variants on top of `FG_Houses.png` warm-brown timber + blue-roof palette (~½ day pixel art). Bundle has the visual language; the modular pieces don't exist yet.
+  - **TileSet:** Wang-style terrain definition in Godot, hand-painted variant assignment.
+- [ ] **Walls — stone (autotile-solvable as-is):**
+  - Import `FG_Fortress.png` tan stonework directly. Build TileSet terrain (~few hours, mostly assembly).
+- [ ] **WallMaterial enum / data path:** wood vs stone is a tag on the BuildJob; the construction pipeline is identical for both. Wood unlocked from start; stone unlocked once player has stone resource (one-step craft from raw stone? — TBD in Phase 6, not here).
 - [ ] **Floors:** wood plank, stone, dirt-cleared
 - [ ] **Doors:** simple swing-open furniture; pawns walk through; pathfinder treats as walkable, walls don't
 - [ ] **Containers (crates):** furniture entity, 4 stacks, 16-chip filter, 5 priorities, all-neighbours-blocked fallback (locked: hold then drop after ~5 sim sec)