fix(harness): gate kickoff/lock entry works in RPC mode (not only interactive)

- Removed event.source === "interactive" guard from entry detection so
  /nuova-domanda and /riprendi-sessione activate lockActive+pendingKickoff
  regardless of source (TUI or RPC prompt).
- Removed event.source !== "interactive" from free-input filter; lock now
  blocks/steers all user input when active, not only interactive keystrokes.
- Added typebox@1.1.38 devDep + fake_pi_runtime.registerCommand (gap from Task 2).
- New test: gate_entry.test.js (2 tests: lock activates on RPC; !-steer passes).
- Full suite: 19/19 pass, zero regressions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

harness/package.json

@@ -5,5 +5,8 @@
   "description": "Pi gate extension for the ThothII NL->SQL harness (widget-descriptor builders + glue)",
   "scripts": {
     "test": "node --test .pi/extensions/gate/__tests__/*.test.js"
+  },
+  "devDependencies": {
+    "typebox": "1.1.38"
   }
 }