feat(hierarchies): trigger templates — per-app fan-out (M4b)

Completes §4.5 templates (M4a shipped routes). A group declares a trigger once;
the tree apply fans it out into one concrete per-app_id trigger on each
descendant app, reusing the M4a expansion engine over the trigger insert path.

- Migration 0054: `trigger_templates` table (group-owned; the whole
  BundleTrigger wire object stored as `spec` JSONB, placeholders unresolved) +
  `triggers.from_template` provenance column + index.
- `template_repo.rs`: trigger-template CRUD + chain-load.
- Manifest: `[group]` `[[trigger_templates]]` (flat: name, kind, script, + kind
  params); build_bundle emits them; rejected on an app node.
- Apply: group nodes reconcile trigger-template rows; tree Phase B expands each
  chain trigger template into a concrete trigger per descendant app —
  placeholders resolved in every spec string leaf, then the typed trigger is
  rebuilt and inserted through the shared `insert_bundle_trigger_tx` (email
  secrets resolved + re-sealed per recipient app). Idempotent via from_template
  (one trigger per template per app; semantic-identity compare → no-op /
  delete+recreate / reap). Collision with a hand-declared trigger or between
  templates is a hard error. Each resolved trigger is re-validated with the
  per-kind shape check (cron/queue/etc.) so a {var:}-injected bad
  schedule/timeout can't slip in.
- Authz: declaring → GroupScriptsWrite; receiving → AppManageTriggers, plus
  AppSecretsRead for email-trigger recipients (parity with hand-declared email).
- Plan/token/report extended for trigger templates; blast radius covers both.
- Tests: tests/templates.rs trigger fan-out (kv + {app_slug}, stable-ids,
  prune-reap); resolve_placeholders_in_json unit test; schema golden reblessed.

Reviewed (no CRITICAL; isolation + per-app email-secret sealing verified
sound). Closed a HIGH validation-parity gap (re-validate resolved triggers) and
a MEDIUM authz gap (AppSecretsRead for email expansions). v1.2 Hierarchies
template work (M4) complete.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/picloud-cli/src/cmds/pull.rs

@@ -237,8 +237,9 @@ pub async fn run(app_ident: &str, dir: &Path, force: bool, mode: OutputMode) ->
         },
         vars: manifest_vars,
         extension_points,
-        // `pull` is app-scoped; route templates are group-owned (§4.5, M4a).
+        // `pull` is app-scoped; templates are group-owned (§4.5).
         route_templates: Vec::new(),
+        trigger_templates: Vec::new(),
     };
 
     std::fs::write(&manifest_path, manifest.to_toml()?)