chore: sync codebase remediation, gameplay systems, and docs

Security & infrastructure:
- Remove unused services/ (auth, spacetimedb) and auth.db
- Add .env.example template, expand .gitignore for env/db files
- Add GitHub Actions CI + commitlint config and workflows
- Add manual vendor chunking and source maps to docs/site vite configs

Shared UI & docs app:
- Add ARIA props and focus-visible rings to Button/Panel
- Add ButtonAsLink primitive; use shared Button in NotFound
- Wire @void-nav/ui into docs app; refresh content pages
- Replace Todo page with Kanban board

Gameplay (Bevy):
- Add ai module (behavior, faction, navigation, perception, spawning, states)
- Add narrative module (events, history, synthesis, ui)
- Refine galaxy contents and in-system flight/scene systems

.env.example

@@ -0,0 +1,35 @@
+# Space-Game Environment Configuration Example
+# Copy this file to .env.local and fill in your actual values
+# NEVER commit .env.local to version control
+
+# ==============================================================================
+# SpacetimeDB Configuration
+# ==============================================================================
+# Primary variables (used by Rust backend)
+SPACETIMEDB_DB_NAME=void-nav-dev
+SPACETIMEDB_HOST=http://127.0.0.1:3000
+
+# Frontend variables (Vite apps)
+VITE_SPACETIMEDB_DB_NAME=void-nav-dev
+VITE_SPACETIMEDB_HOST=http://127.0.0.1:3000
+
+# ==============================================================================
+# Better Auth Configuration
+# ==============================================================================
+# Generate a secure random secret for production:
+# openssl rand -base64 32
+BETTER_AUTH_SECRET=your-secret-here-generate-with-openssl-rand-base64-32
+BETTER_AUTH_URL=http://localhost:4000
+
+# ==============================================================================
+# Application URLs
+# ==============================================================================
+VITE_DOCS_URL=http://localhost:5173/docs
+VITE_GAME_URL=http://localhost:5175
+
+# ==============================================================================
+# CORS Configuration (for auth service)
+# ==============================================================================
+# Comma-separated list of allowed origins for CORS
+# Example: CORS_ALLOWED_ORIGINS=https://docs.example.com,https://site.example.com
+CORS_ALLOWED_ORIGINS=http://localhost:5173,http://localhost:5174,http://localhost:5175