T03: plugin system framework + lifecycle + migrations + event bus + DI

- Plugin registry with discover/install/activate/deactivate/uninstall lifecycle
- PluginManifest Pydantic v2 schema (name, version, dependencies, routes, events, migrations)
- BasePlugin abstract class with lifecycle hooks (on_install/activate/deactivate/uninstall)
- Migration runner with tenant_id validator (rejects tables without tenant_id)
- Event bus integration: register/unregister listeners on activate/deactivate
- Service container DI: plugins receive db, cache, event_bus, storage, notifications
- Idempotent operations (activate active=200, deactivate inactive=200)
- UI registry for frontend component registration
- 47 new tests (14 ACs + 33 unit tests), 103 total tests pass
- Migration 0003: plugins + plugin_migrations tables
- Coverage: 85.92% for plugin modules

app/routes/plugins.py

@@ -0,0 +1,139 @@
+"""Plugin routes — list, install, activate, deactivate, uninstall, manifest schema."""
+
+from __future__ import annotations
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.db import get_db
+from app.deps import require_admin
+from app.plugins.migration_runner import MigrationValidationError
+from app.services.plugin_service import get_plugin_service
+
+router = APIRouter(prefix="/api/v1/plugins", tags=["plugins"])
+
+
+@router.get("")
+async def list_plugins(
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_admin),
+):
+    """List all plugins with their current status (discovered, installed, active, inactive)."""
+    service = get_plugin_service()
+    plugins = await service.list_plugins(db)
+    return {"plugins": plugins, "total": len(plugins)}
+
+
+@router.get("/manifest")
+async def get_manifest_schema(
+    current_user: dict = Depends(require_admin),
+):
+    """Get the plugin manifest schema documentation."""
+    service = get_plugin_service()
+    return service.get_manifest_schema()
+
+
+@router.post("/{name}/install")
+async def install_plugin(
+    name: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_admin),
+):
+    """Install a plugin by name. Runs migrations and creates DB record.
+
+    Idempotent: returns 200 if already installed.
+    """
+    import uuid as uuid_mod
+    service = get_plugin_service()
+    try:
+        result = await service.install_plugin(
+            db, name,
+            tenant_id=uuid_mod.UUID(current_user["tenant_id"]),
+            user_id=uuid_mod.UUID(current_user["user_id"]),
+        )
+        return result
+    except ValueError as exc:
+        if "not found" in str(exc).lower():
+            raise HTTPException(404, detail={"detail": str(exc), "code": "plugin_not_found"})
+        raise HTTPException(400, detail={"detail": str(exc), "code": "plugin_error"})
+    except MigrationValidationError as exc:
+        raise HTTPException(422, detail={"detail": str(exc), "code": "migration_validation_error"})
+
+
+@router.post("/{name}/activate")
+async def activate_plugin(
+    name: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_admin),
+):
+    """Activate a plugin by name. Registers event listeners and routes.
+
+    Idempotent: returns 200 if already active.
+    """
+    import uuid as uuid_mod
+    service = get_plugin_service()
+    try:
+        result = await service.activate_plugin(
+            db, name,
+            tenant_id=uuid_mod.UUID(current_user["tenant_id"]),
+            user_id=uuid_mod.UUID(current_user["user_id"]),
+        )
+        return result
+    except ValueError as exc:
+        if "not installed" in str(exc).lower():
+            raise HTTPException(400, detail={"detail": str(exc), "code": "plugin_not_installed"})
+        if "not found" in str(exc).lower():
+            raise HTTPException(404, detail={"detail": str(exc), "code": "plugin_not_found"})
+        raise HTTPException(400, detail={"detail": str(exc), "code": "plugin_error"})
+
+
+@router.post("/{name}/deactivate")
+async def deactivate_plugin(
+    name: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_admin),
+):
+    """Deactivate a plugin by name. Unregisters event listeners and routes.
+
+    Idempotent: returns 200 if already inactive.
+    """
+    import uuid as uuid_mod
+    service = get_plugin_service()
+    try:
+        result = await service.deactivate_plugin(
+            db, name,
+            tenant_id=uuid_mod.UUID(current_user["tenant_id"]),
+            user_id=uuid_mod.UUID(current_user["user_id"]),
+        )
+        return result
+    except ValueError as exc:
+        if "not found" in str(exc).lower():
+            raise HTTPException(404, detail={"detail": str(exc), "code": "plugin_not_found"})
+        raise HTTPException(400, detail={"detail": str(exc), "code": "plugin_error"})
+
+
+@router.delete("/{name}")
+async def uninstall_plugin(
+    name: str,
+    remove_data: bool = Query(False),
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_admin),
+):
+    """Uninstall a plugin. Optionally drop plugin-created tables with remove_data=true.
+
+    Returns 200 with uninstalled status. Idempotent for already-uninstalled plugins.
+    """
+    import uuid as uuid_mod
+    service = get_plugin_service()
+    try:
+        result = await service.uninstall_plugin(
+            db, name,
+            remove_data=remove_data,
+            tenant_id=uuid_mod.UUID(current_user["tenant_id"]),
+            user_id=uuid_mod.UUID(current_user["user_id"]),
+        )
+        return result
+    except ValueError as exc:
+        if "not found" in str(exc).lower():
+            raise HTTPException(404, detail={"detail": str(exc), "code": "plugin_not_found"})
+        raise HTTPException(400, detail={"detail": str(exc), "code": "plugin_error"})