feat: outbound webhooks — signed event delivery + delivery log

Every audited action now emits a "resource.action" event (bare actions
get resource-qualified; already-qualified actions like service.clone
pass through). Webhooks subscribe per-user with exact names, resource.*
wildcards, or *.

- schema: outbound_webhooks + webhook_deliveries (sqlc + goose)
- dispatcher: 4 workers, 512-queue, 3 attempts with backoff, 10s timeout;
  deliveries record status/http-code/body(4KiB)/duration
- signing: X-Containr-Signature sha256=<hmac> over raw body;
  X-Containr-Event + X-Containr-Delivery headers; custom headers per hook
- api: CRUD + /deliveries + /test (ping) under authed group
- fix: SetAuditDB never called — LogAudit was a silent no-op at every
  call site; now wired at boot
- coverage: service create/delete audited (previously uninstrumented)
- cli: containr webhooks list|create|update|delete|deliveries|test
- mcp: 6 tools, delete requires confirm
- frontend: /settings/webhooks page — list/create/expand-deliveries/
  test/disable/delete, secret-shown-once banner; nav + account menu
- openapi + regenerated types; CLI.md + docs snapshot; roadmap ticks

docs/guides/CLI.md

@@ -78,6 +78,10 @@ security scan|vulnerabilities|metrics
 gateway services|keys|analytics  (admin)
 admin overview|users|settings|audit-logs
 notifications list|read
+webhooks list|create|update|delete|deliveries|test
+                               outbound signed webhooks — create <name> <url>
+                               --event 'service.*' (repeatable, '*' = all);
+                               deliveries are HMAC-signed (X-Containr-Signature)
 up                               deploy the current directory
 ```