docs+install: sweep deploy/start → castle apply

Update the README, AGENTS.md, install.sh, and docs/ for the converge
model: one `castle apply [name] [--plan]` replaces `deploy && start` and
the per-kind enable/disable/install/start/stop verbs. CLI references now
list apply + restart (the imperative bounce) + logs; recipes use
`castle apply`; "turn it off" is documented as `enabled: false` + apply.
install.sh's next-steps collapse to a single `castle apply`.

Verified: no retired-verb command instructions remain in any markdown;
install.sh syntax OK; live `castle apply --plan` reports converged;
doctor all-green; core 129 / cli 31 / api 59 pass.

docs/stacks/supabase.md

@@ -119,7 +119,7 @@ leaves the schema intact (and says so). To destroy the data too:
 castle delete my-app --purge-data      # drop schema my_app cascade
 ```
 
-`castle deploy` then prunes the schema from `PGRST_DB_SCHEMAS`; **restart the
+`castle apply` then prunes the schema from `PGRST_DB_SCHEMAS`; **restart the
 `supabase` service** for PostgREST to pick up the added/removed schema list.
 
 ## Auth, RLS & the three privacy layers
@@ -161,7 +161,7 @@ service itself is likewise at `supabase.<gateway.domain>`.) See
 castle program create my-app --stack supabase --description "..."   # scaffold + register
 castle program build my-app        # apply unapplied migrations to the substrate
 castle program test  my-app        # deno test over functions/ (if deno present)
-castle deploy && castle gateway reload    # serve the static UI at /my-app/
+castle apply    # serve the static UI at /my-app/
 ```
 
 ## Scaffolding