chore(meta): add project directory scaffold

Create client/, server/, tooling/, tests/, .config/ (tracked) and
.cache/ (gitignored). Update CLAUDE.md project structure to reflect
the new layout including workshops directory.

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

.gitignore

@@ -1,3 +1,6 @@
+# Build and cache
+.cache/
+
 # Database
 db/commonwealth.db
 db/commonwealth.db-wal

CLAUDE.md

@@ -8,13 +8,18 @@ A top-down immersive sim — occlusion-based detective game with combat elements
 ## Project Structure
 
 ```
-DECISIONS.md          # Confirmed decisions (D-001+), open questions (Q-001+)
-TEAM.md               # Team roster and roles
+client/               # Godot 4 client (D-020)
+server/               # Rust/bevy_ecs simulation server (D-020)
+tooling/              # Build tools, scripts, asset pipelines
+tests/                # Integration and end-to-end tests
+.config/              # Configuration files (linters, formatters, CI)
+.cache/               # Local caches for testing/linting (gitignored)
 docs/
   discussions/        # Discussion rounds (all rounds archived here per D-022)
   briefings/          # Per-agent context briefings (maintained by Qatux)
   architecture/       # Technical architecture documents
   design/             # Game design documents
+  workshops/          # Workshop briefs and outputs (per-workshop subdirectories)
 db/
   commonwealth.db     # SQLite ticketing database
   schema.sql          # Database schema
@@ -25,6 +30,8 @@ db/
 .claude/
   agents/             # Agent personality files
   skills/             # Skill definitions
+DECISIONS.md          # Confirmed decisions (D-001+), open questions (Q-001+)
+TEAM.md               # Team roster and roles
 ```
 
 ## Agent Instructions