feat: Implement scene rulebook and validation engine

- Added a new SceneRulebook system to manage data-driven validation rules for actions.
- Introduced rule checks for actions like "take", "open", "move", "introduce", and "describe".
- Created a rulebook engine to evaluate conditions and enforce rules during action validation.
- Enhanced action handling with support for scene entry and character descriptions.
- Updated the architecture documentation to reflect the new rule-based validation approach.
- Added new endpoints and improved the persistence layer for rulebooks.

thoughts.md

@@ -14,6 +14,12 @@
   - `open door` before key -> `locked_requires_key`
   - `take key` -> success
   - `open door` after key -> success
+- Scene-entry support added:
+  - `introduce` is now a first-class action
+  - rooms can declare `is_joinable`
+  - characters can declare `is_social`
+  - successful introduction moves a character from offstage into the actor's current room
+  - `introduce` can also create a new social character when the named target does not already exist
 
 ## Architecture Now
 - Core contracts in `app/src/contracts/`:
@@ -31,7 +37,36 @@
 - Persistence:
   - `app/src/db.ts` with tables `turns`, `actions`, `validation_results`, `entities`, `world_states`
 - App seed domain:
-  - `app/src/app.ts` door/key world (`room_start`, `room_exit`, `player`, `door_1`, `key_1`)
+  - `app/src/app.ts` door/key world (`room_start`, `room_exit`, `room_offstage`, `player`, `groundskeeper`, `door_1`, `key_1`)
+
+## Scene Entry Rules
+- `introduce` validates against deterministic affordances:
+  - target must exist
+  - target must be a character
+  - target must have `is_social: true`
+  - actor must be in a valid room
+  - room must have `is_joinable: true`
+  - target must not already be in that room
+- If no existing target entity is resolved but a character name is present, `introduce` may create a new character directly into the current room.
+
+## Character Description (NEW)
+- `describe` action adds traits to characters:
+  - Syntax: `"describe the merchant as shrewd and quick"`
+  - Traits are stored in `character.attributes.traits[]`
+  - Multi-sentence support: `"introduce a merchant. describe the merchant as shrewd and quick."`
+- Validation rules:
+  - target character must exist (or will be created by introduce in same turn)
+  - actor and target must be in same room (for existing targets)
+  - supports forward-reference to entities created in the same turn
+- Multi-action parsing:
+  - Sentences split on `/[.!?]+/`
+  - Each sentence becomes a separate action
+  - Validation accounts for entities created by introduce actions in the same turn
+- On success:
+  - target location becomes the actor's location
+  - `in_scene` is set to `true`
+  - `last_introduced_by` is recorded
+  - newly created characters default to `type: character`, `is_social: true`, `in_scene: true`
 
 ## New Endpoint
 - Added `POST /api/reset` in `app/src/index.ts`
@@ -50,5 +85,5 @@
 
 ## Remaining Checks
 1. Frontend build pass completed in container (`docker compose exec frontend npm run build`).
-2. Validate inspector UX manually against the door/key flow.
+2. Validate inspector UX manually against the door/key plus introduce flow.
 3. Expand parser coverage only within current clean MVP domain.