fix(tui): eliminate pinned output duplication and reduce render overhead

rebuildChatFromMessages() called populatePinnedFromMessages() which
re-populated the pinned zone with text already present in the chat
history, causing visible duplication during session state changes.
Additionally, the spinner interval at 80ms generated ~12.5 renders/s
for a purely cosmetic animation, and clearOnShrink triggered
unnecessary full redraws during pinned-zone transitions.

- Remove populatePinnedFromMessages() from rebuildChatFromMessages()
  and add pinnedMessageContainer.clear() instead — the streaming
  lifecycle in chat-controller manages pinned content during active work
- Reduce spinner interval 80ms→200ms with render-batching that skips
  redundant renders when streaming already triggers requestRender()
- Debounce clearOnShrink: defer full redraw by one render tick so
  pinned-clear→new-streaming transitions avoid a wasted full redraw
- Increase notification widget safety-net timer 5s→30s since the
  store subscription already handles push-based updates

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/pi-coding-agent/src/modes/interactive/components/dynamic-border.ts

@@ -17,6 +17,7 @@ export class DynamicBorder implements Component {
 	private spinnerIndex = 0;
 	private spinnerInterval: NodeJS.Timeout | null = null;
 	private spinnerColorFn?: (str: string) => string;
+	private lastExternalRender = 0;
 
 	constructor(color: (str: string) => string = (str) => {
 		try { return theme.fg("border", str); } catch { return str; }
@@ -31,7 +32,7 @@ export class DynamicBorder implements Component {
 
 	/**
 	 * Start an animated spinner that prepends to the label.
-	 * The spinner rotates every 80ms and triggers a re-render via the TUI.
+	 * The spinner rotates every 200ms and triggers a re-render via the TUI.
 	 */
 	startSpinner(ui: TUI, colorFn: (str: string) => string): void {
 		this.stopSpinner();
@@ -39,8 +40,12 @@ export class DynamicBorder implements Component {
 		this.spinnerIndex = 0;
 		this.spinnerInterval = setInterval(() => {
 			this.spinnerIndex = (this.spinnerIndex + 1) % this.spinnerFrames.length;
-			ui.requestRender();
-		}, 80);
+			// Only trigger standalone render if no other source rendered recently.
+			// During active streaming, message_update already calls requestRender().
+			if (Date.now() - this.lastExternalRender > 200) {
+				ui.requestRender();
+			}
+		}, 200);
 		ui.requestRender();
 	}
 
@@ -64,6 +69,7 @@ export class DynamicBorder implements Component {
 	}
 
 	render(width: number): string[] {
+		this.lastExternalRender = Date.now();
 		const spinnerPrefix = this.spinnerInterval && this.spinnerColorFn
 			? this.spinnerColorFn(this.spinnerFrames[this.spinnerIndex]) + " "
 			: "";

packages/pi-coding-agent/src/modes/interactive/interactive-mode.ts

@@ -2306,9 +2306,13 @@ export class InteractiveMode {
 
 	private rebuildChatFromMessages(): void {
 		this.chatContainer.clear();
+		this.pinnedMessageContainer.clear();
 		const context = this.sessionManager.buildSessionContext();
 		this.renderSessionContext(context);
-		this.populatePinnedFromMessages(context.messages);
+		// Pinned content NOT re-populated here — the streaming lifecycle in
+		// chat-controller.ts manages the pinned zone during active work.
+		// populatePinnedFromMessages() remains in renderInitialMessages()
+		// for the session-resume case at startup.
 	}
 
 	/**

packages/pi-tui/src/tui.ts

@@ -255,6 +255,7 @@ export class TUI extends Container {
 	private cellSizeQueryPending = false;
 	private showHardwareCursor = process.env.PI_HARDWARE_CURSOR === "1" || process.env.TERM_PROGRAM === "WarpTerminal";
 	private clearOnShrink = process.env.PI_CLEAR_ON_SHRINK === "1"; // Clear empty rows when content shrinks (default: off)
+	private _shrinkDebounceActive = false;
 	private maxLinesRendered = 0; // Track terminal's working area (max lines ever rendered)
 	private previousViewportTop = 0; // Track previous viewport top for resize-aware cursor moves
 	private fullRedrawCount = 0;
@@ -723,9 +724,25 @@ export class TUI extends Container {
 		// (overlays need the padding, so only do this when no overlays are active)
 		// Configurable via setClearOnShrink() or PI_CLEAR_ON_SHRINK=0 env var
 		if (this.clearOnShrink && newLines.length < this.maxLinesRendered && this.overlayStack.length === 0) {
-			logRedraw(`clearOnShrink (maxLinesRendered=${this.maxLinesRendered})`);
-			fullRender(true);
-			return;
+			if (!this._shrinkDebounceActive) {
+				// First shrink detection: defer the full redraw by one tick.
+				// If content grows back immediately (pinned clear → new streaming),
+				// the full redraw is avoided.
+				this._shrinkDebounceActive = true;
+				// Do NOT update maxLinesRendered here — keep the old value so the
+				// condition `newLines.length < maxLinesRendered` still triggers on
+				// the next render if content stays shrunk.
+				logRedraw(`clearOnShrink deferred (maxLinesRendered=${this.maxLinesRendered})`);
+				// Fall through to differential render for this frame
+			} else {
+				// Still shrunk on second render — commit the full redraw
+				this._shrinkDebounceActive = false;
+				logRedraw(`clearOnShrink committed (maxLinesRendered=${this.maxLinesRendered})`);
+				fullRender(true);
+				return;
+			}
+		} else {
+			this._shrinkDebounceActive = false;
 		}
 
 		// Find first and last changed lines

src/resources/extensions/gsd/notification-widget.ts

@@ -1,6 +1,6 @@
 // GSD Extension — Notification Widget
 // Always-on ambient widget rendered belowEditor showing unread count and
-// the most recent notification message. Refreshes every 5 seconds.
+// the most recent notification message. Refreshes every 30 seconds.
 // Widget key: "gsd-notifications", placement: "belowEditor"
 
 import type { ExtensionContext } from "@gsd/pi-coding-agent";
@@ -19,7 +19,7 @@ export function buildNotificationWidgetLines(): string[] {
 
 // ─── Widget init ────────────────────────────────────────────────────────
 
-const REFRESH_INTERVAL_MS = 5_000;
+const REFRESH_INTERVAL_MS = 30_000;
 
 /**
  * Initialize the always-on notification widget (belowEditor).