refactor: Align vocabulary — component → program / deployment

Canonical terms (see docs/registry.md glossary):
- program: any catalog entry (tool/daemon/frontend) — the software
- service / job: how a program is deployed (systemd .service / .timer)
- deployment: umbrella for the unified service+job+program view

Changes:
- core: ServiceSpec/JobSpec component: → program: (component accepted as
  back-compat validation_alias); DeployedComponent → Deployment.
- api: ComponentSummary/Detail → DeploymentSummary/Detail; GET /components
  → /deployments; GatewayRoute.component → program; GatewayInfo
  .component_count → deployment_count; ServiceActionResponse/action keys
  component → program.
- app: matching type renames, /components → /deployments hook, route
  /component/:name → /deployment/:name, GatewayRoute.program.
- docs: component-registry.md → registry.md (+ canonical glossary);
  CLAUDE.md endpoint list refreshed (drop removed /tools, add typed
  program/service/job + config routes).

Tests: core 92, cli 24, api 52 green; app build clean; ruff clean.

castle-api/src/castle_api/services.py

@@ -108,7 +108,7 @@ async def _do_action(name: str, action: str) -> JSONResponse:
         asyncio.create_task(_deferred_systemctl(action, unit))
         return JSONResponse(
             status_code=202,
-            content={"component": name, "action": action, "status": "accepted"},
+            content={"program": name, "action": action, "status": "accepted"},
         )
 
     ok, output = await _systemctl(action, unit)
@@ -120,7 +120,7 @@ async def _do_action(name: str, action: str) -> JSONResponse:
     await _broadcast_health_with_override(name, unit_status)
 
     return JSONResponse(
-        content={"component": name, "action": action, "status": unit_status},
+        content={"program": name, "action": action, "status": unit_status},
     )