feat(automations): moteur de regles if-this-then-that (v5.1.0 roadmap, bump v5.2.0)

Moteur d'automatisation complet : declencheurs (evenement / cron / bouton),
conditions combinables (eq, neq, contains, is_empty, is_not_empty, changed)
et actions (webhook, set_property, create_page, notify).

- Migration v5 : tables `automations` + `automation_runs` (avec index).
- Service `app/services/automations.py` : fire_event, cron_due (`*/N`,
  minute fixe, @hourly/@daily), scheduler de fond dans le lifespan.
- Router `app/routers/automations.py` : CRUD `/workspace/automations`,
  historique des executions, run manuel + run bouton `/api/automations/{id}/run`
  (exempt CSRF, comme `/api/agent`).
- Hooks d'evenements dans collections.py / board.py / workspace.py
  (collection.* et page.* : created/updated/deleted/moved).
- Bloc `button` dans l'editeur (menu slash) : declenche une regle au clic,
  picker d'automation inline, serialisation automations_id/name.
- Panneau Automations dans le Settings (creer/editer/activer/desactiver/
  lancer/supprimer + historique), collection scope + JSON conditions/actions.
- 11 tests `tests/test_automations.py` ; suite complete pytest 289 verte.
- Version bump 5.2.0 (VERSION, app/main.py, CHANGELOG).

app/routers/workspace.py

@@ -12,6 +12,7 @@ from fastapi.responses import HTMLResponse, StreamingResponse
 
 from app.db import get_conn
 from app.auth.session import SessionManager
+from app.services.automations import fire_event
 
 logger = logging.getLogger(__name__)
 router = APIRouter(tags=["workspace"], prefix="/workspace")
@@ -289,6 +290,12 @@ async def apply_page_template(request: Request, collection_id: int, tid: int):
             (collection_id, body.get("title", "New Page"), max_pos, tmpl["property_values_json"]),
         )
         conn.commit()
+    await fire_event("page.created", {
+        "page_id": cur.lastrowid,
+        "collection_id": collection_id,
+        "title": body.get("title", "New Page"),
+        "properties": json.loads(tmpl["property_values_json"]) if tmpl["property_values_json"] else {},
+    })
     return {"id": cur.lastrowid, "status": "created"}