fix(ui): stream phase progress without gates

harness/.pi/extensions/tht-gate.js

@@ -52,6 +52,11 @@ import {
 } from "./gate/disambiguation/index.js";
 import { isReserved } from "./gate/core/reserved-labels.mjs";
 
+// Machine-readable RPC notification consumed by SessionBridge. Pi's extension API
+// exposes notify/input but no custom client-event emitter, so this reserved prefix is
+// the narrow transport contract for phase progress that does not require a human gate.
+export const PHASE_STARTED_NOTIFICATION_PREFIX = "__tht_phase_started__:";
+
 // Load the workflow contract once when Pi loads the extension. Asking the model to
 // discover/read the skill as its first action proved unreliable with remote models:
 // they can spend the whole RPC turn exploring the repository before opening the exact
@@ -596,6 +601,18 @@ export default function (pi) {
 	let lastSteered = false;
 	let pendingKickoff = null;
 	let activeSessionId = null;
+	const announcedPhases = new Map();
+	const announceCurrentPhase = async (ctx, session) => {
+		if (ctx.mode !== "rpc" || typeof session !== "string" || !session.trim()) return;
+		try {
+			const phase = phaseId(ctx, currentPhase(ctx, session));
+			if (!/^F[1-8]$/.test(phase) || announcedPhases.get(session) === phase) return;
+			await ctx.ui.notify(`${PHASE_STARTED_NOTIFICATION_PREFIX}${phase}`, "info");
+			announcedPhases.set(session, phase);
+		} catch {
+			// Progress reporting is observational: it must never block the workflow.
+		}
+	};
 	const memoryGate = createMemoryGate({
 		workflow: {
 			activate: () => {
@@ -748,7 +765,8 @@ export default function (pi) {
 
 	// 3) BEFORE_AGENT_START: one-shot kickoff injection (appends the operational
 	//    instructions to the system prompt on the turn that starts/resumes a session).
-	pi.on("before_agent_start", (event, ctx) => {
+	pi.on("before_agent_start", async (event, ctx) => {
+		await announceCurrentPhase(ctx, process.env.THT_SESSION);
 		if (!pendingKickoff) return undefined;
 		const sessionId = process.env.THT_SESSION;
 		const isProvidedNewSession =
@@ -789,9 +807,18 @@ export default function (pi) {
 			lastSteered = false;
 		}
 		activeSessionId = null;
+		announcedPhases.clear();
 		_phaseMetaCache = null;
 	});
 
+	// A reviewer tool is the ownership boundary that persists a decision and may
+	// advance the folded workflow phase. Observe the persisted phase after the tool
+	// completes, including auto-approved phases that never open a human widget.
+	pi.on("tool_result", async (event, ctx) => {
+		const session = typeof event.input?.session === "string" ? event.input.session : null;
+		if (session) await announceCurrentPhase(ctx, session);
+	});
+
 	// 5) AGENT_END prose safety net: if the model emits prose instead of a reviewer_*
 	//    tool call (and the lock is active), nudge it back to the gate tools.
 	pi.on("agent_end", async (event) => {