feat(coding-agent): add extension project trust decisions

packages/coding-agent/examples/extensions/README.md

@@ -19,6 +19,7 @@ cp permission-gate.ts ~/.pi/agent/extensions/
 | Extension | Description |
 |-----------|-------------|
 | `permission-gate.ts` | Prompts for confirmation before dangerous bash commands (rm -rf, sudo, etc.) |
+| `project-trust.ts` | Demonstrates the `project_trust` event for user/global and CLI extensions |
 | `protected-paths.ts` | Blocks writes to protected paths (.env, .git/, node_modules/) |
 | `confirm-destructive.ts` | Confirms before destructive session actions (clear, switch, fork) |
 | `dirty-repo-guard.ts` | Prevents session changes with uncommitted git changes |

packages/coding-agent/examples/extensions/project-trust.ts

@@ -0,0 +1,59 @@
+/**
+ * Project Trust Extension
+ *
+ * Demonstrates the project_trust event. Install globally or pass via -e:
+ *
+ *   mkdir -p ~/.pi/agent/extensions
+ *   cp packages/coding-agent/examples/extensions/project-trust.ts ~/.pi/agent/extensions/
+ *
+ * Or:
+ *
+ *   pi -e packages/coding-agent/examples/extensions/project-trust.ts
+ *
+ * Try it in a project containing .pi, AGENTS.md/CLAUDE.md, or .agents/skills.
+ */
+
+import type { ExtensionAPI, ProjectTrustEventResult } from "@earendil-works/pi-coding-agent";
+
+export default function (pi: ExtensionAPI) {
+	let loadCount = 0;
+	loadCount++;
+
+	// Multiple handlers in one extension are allowed. The first handler that returns
+	// { trusted } wins and suppresses the built-in trust prompt. A project_trust
+	// handler must return a decision.
+	pi.on("project_trust", async (event, ctx): Promise<ProjectTrustEventResult> => {
+		ctx.ui.notify(`project_trust fired for ${event.cwd} (mode: ${ctx.mode}, load: ${loadCount})`, "info");
+
+		if (!ctx.hasUI) {
+			return { trusted: false };
+		}
+
+		const choice = await ctx.ui.select(`Project trust for:\n${event.cwd}`, [
+			"Trust and remember",
+			"Trust with note and remember",
+			"Trust this session",
+			"Do not trust this session",
+		]);
+
+		if (choice === "Trust with note and remember") {
+			const note = await ctx.ui.input("Project trust note", "Optional note for this demo");
+			ctx.ui.notify(note ? `Recorded demo note: ${note}` : "No demo note entered", "info");
+			return { trusted: true, remember: true };
+		}
+		if (choice === "Trust and remember") {
+			return { trusted: true, remember: true };
+		}
+		if (choice === "Trust this session") {
+			return { trusted: true };
+		}
+		if (choice === "Do not trust this session") {
+			return { trusted: false };
+		}
+		return { trusted: false };
+	});
+
+	pi.on("session_start", (_event, ctx) => {
+		ctx.ui.notify(`project-trust example loaded after trust resolution in ${ctx.cwd}`, "info");
+	});
+}