chore(harness): quietStartup + project-local trust for clean RPC spawn

Set quietStartup:true in .pi/settings.json to suppress Pi banner on RPC stdout.
Add test pinning both quietStartup and theme values. Document project-local trust
requirement (--approve) so no trust prompt blocks RPC loop iteration.

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

harness/.pi/extensions/gate/__tests__/settings.test.js

@@ -0,0 +1,10 @@
+const test = require("node:test");
+const assert = require("node:assert");
+const fs = require("node:fs");
+const path = require("node:path");
+
+test("settings.json abilita quietStartup", () => {
+  const s = JSON.parse(fs.readFileSync(path.join(__dirname, "../../../settings.json"), "utf8"));
+  assert.equal(s.quietStartup, true);
+  assert.equal(s.theme, "thothii-mono");
+});

harness/.pi/settings.json

@@ -1,3 +1,4 @@
 {
-  "theme": "thothii-mono"
+  "theme": "thothii-mono",
+  "quietStartup": true
 }

harness/docs/rpc-readiness-findings.md

@@ -255,3 +255,9 @@ closed set; `ctx.ui.custom` is a no-op in RPC mode.
 
 **Tasks 3–4 both require gate adaptation.** No part of the existing mechanism works in RPC
 mode without changes.
+
+---
+
+## Project-local trust for clean RPC spawn
+
+To ensure RPC stdout remains clean (no interactive trust prompts polluting the JSONL stream), project-local files must be pre-approved via the `--approve` flag or pre-trusted settings. Task 9 sets `quietStartup: true` in `.pi/settings.json` to suppress Pi's banner; access to this project-local config must be granted ahead of time so the RPC spawn does not pause for a trust confirmation, which would block the command loop.