fix(home): swap the home surface on a fold whatever width the page loaded at

Folding a phone on the home screen left the welcome screen up when the page
had loaded wide (#702): the phone overview's breakpoint listener was wired
from its first show, which a wide-loaded page never reaches. Both home
screens' breakpoint listeners are now installed once from init() and act
only while a home surface is up.

A rail render queued just before the fold could also unhide the desktop
rail behind the phone overview; the debounced refresh now asks again when
it fires.

Tests: test/home-breakpoint-listeners.test.ts (gate) and
test/home-breakpoint-swap.browser.test.ts (browser suite: wide-first and
narrow-first across 599/600 and 767/768, plus a height-only resize).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/web/public/app.js

@@ -1232,6 +1232,11 @@ class CodemanApp {
     // and then applies the sidebar variant on top — do not call both.
     this.applySessionListLayout();
     this.applyTabOrientation();
+    // The home screens' breakpoint listeners, once, before any home surface is
+    // shown: a fold or unfold must swap the surface whichever width the page
+    // loaded at (#702). Both self-gate on a home screen being up.
+    this._wireMobileOverviewBreakpoint?.();
+    this._wireHomeSessionsBreakpoint?.();
     this.initTabRailResize?.();
     this.applyMonitorVisibility();
     this.applyLineageLineSettings?.();

src/web/public/home-sessions.js

@@ -126,20 +126,31 @@ Object.assign(CodemanApp.prototype, {
     this._stopHomeSessionsClock();
   },
 
-  /** Re-render only when showing (called from the tab renderer's tail). */
+  /**
+   * Re-render only when showing (called from the tab renderer's tail). Asked
+   * again when the debounce fires: `renderHomeSessions()` unhides the column,
+   * so a render queued just before a fold to phone width hid it (#702) would
+   * otherwise bring it back behind the phone overview.
+   */
   _refreshHomeSessionsIfVisible() {
     if (!this.isHomeSessionsVisible()) return;
-    this._debouncedCall('homeSessions', () => this.renderHomeSessions(), 150);
+    this._debouncedCall(
+      'homeSessions',
+      () => {
+        if (this.isHomeSessionsVisible() && this.shouldShowHomeSessions()) this.renderHomeSessions();
+      },
+      150
+    );
   },
 
   /**
-   * One delegated click listener for every row, plus a width listener so
-   * resizing the window while on the home screen adds or drops the column
-   * instead of leaving it overlapping the content it was sized to clear.
+   * One delegated click listener for every row. The width listener lives in
+   * `_wireHomeSessionsBreakpoint()`, installed at startup.
    */
   _wireHomeSessions(el) {
     if (this._homeSessionsWired) return;
     this._homeSessionsWired = true;
+    this._wireHomeSessionsBreakpoint();
 
     el.addEventListener('click', (event) => {
       const target = event.target?.closest?.('[data-hs-action]');
@@ -150,20 +161,29 @@ Object.assign(CodemanApp.prototype, {
         void this.openWebview?.(target.dataset.hsWebview);
       }
     });
+  },
 
-    if (window.matchMedia) {
-      const mq = window.matchMedia(`(min-width: ${HOME_SESSIONS_MIN_WIDTH}px)`);
-      const onChange = () => {
-        // Only relevant while the welcome screen is up; entering a session
-        // re-decides through hideWelcome()/showWelcome() anyway.
-        if (this.activeSessionId) return;
-        const overlay = document.getElementById('welcomeOverlay');
-        if (!overlay || !overlay.classList.contains('visible')) return;
-        this.showHomeSessions();
-      };
-      if (mq.addEventListener) mq.addEventListener('change', onChange);
-      else if (mq.addListener) mq.addListener(onChange);
-    }
+  /**
+   * Add or drop the column when the window crosses its width gate, so it never
+   * overlaps the content it was sized to clear. Installed ONCE at startup
+   * (`init()` in app.js) like the phone overview's breakpoint listener, so a
+   * page that loads on a phone and is unfolded to desktop width gets it too
+   * (#702). Idempotent.
+   */
+  _wireHomeSessionsBreakpoint() {
+    if (this._homeSessionsBreakpointWired || !window.matchMedia) return;
+    this._homeSessionsBreakpointWired = true;
+    const mq = window.matchMedia(`(min-width: ${HOME_SESSIONS_MIN_WIDTH}px)`);
+    const onChange = () => {
+      // Only relevant while the welcome screen is up; entering a session
+      // re-decides through hideWelcome()/showWelcome() anyway.
+      if (this.activeSessionId) return;
+      const overlay = document.getElementById('welcomeOverlay');
+      if (!overlay || !overlay.classList.contains('visible')) return;
+      this.showHomeSessions();
+    };
+    if (mq.addEventListener) mq.addEventListener('change', onChange);
+    else if (mq.addListener) mq.addListener(onChange);
   },
 
   // ═══════════════════════════════════════════════════════════════

src/web/public/mobile-overview.js

@@ -385,13 +385,13 @@ Object.assign(CodemanApp.prototype, {
   },
 
   /**
-   * One delegated click listener for every row, plus a breakpoint listener so
-   * rotating or unfolding while on the home screen swaps to the right surface
-   * instead of stranding a phone layout on a tablet-width viewport.
+   * One delegated click listener for every row. The breakpoint listener lives
+   * in `_wireMobileOverviewBreakpoint()`, installed at startup.
    */
   _wireMobileOverview(el) {
     if (this._mobileOverviewWired) return;
     this._mobileOverviewWired = true;
+    this._wireMobileOverviewBreakpoint();
 
     el.addEventListener('click', (event) => {
       const target = event.target && event.target.closest && event.target.closest('[data-mo-action]');
@@ -426,18 +426,34 @@ Object.assign(CodemanApp.prototype, {
         this.showWebviewModal();
       }
     });
+  },
 
-    if (window.matchMedia) {
-      const mq = window.matchMedia(MOBILE_OVERVIEW_PHONE_QUERY);
-      const onChange = () => {
-        // Only relevant while a home surface is up; entering a session re-decides
-        // through hideWelcome()/showWelcome() anyway.
-        if (this.activeSessionId) return;
-        if (typeof this.showWelcome === 'function') this.showWelcome();
-      };
-      if (mq.addEventListener) mq.addEventListener('change', onChange);
-      else if (mq.addListener) mq.addListener(onChange);
-    }
+  /**
+   * Swap the home surface when the width crosses the phone breakpoint (rotate,
+   * fold, unfold), so a phone layout is never stranded on a tablet-width
+   * viewport and the welcome screen never on a phone-width one.
+   *
+   * Installed ONCE at startup (`init()` in app.js), not on the first show: a
+   * page that loads wide never shows the phone overview, so a listener wired
+   * from there was missing on exactly the fold that needed it (#702). Idempotent,
+   * so the call from `_wireMobileOverview()` adds nothing after startup.
+   */
+  _wireMobileOverviewBreakpoint() {
+    if (this._mobileOverviewBreakpointWired || !window.matchMedia) return;
+    this._mobileOverviewBreakpointWired = true;
+    const mq = window.matchMedia(MOBILE_OVERVIEW_PHONE_QUERY);
+    const onChange = () => {
+      // Only relevant while a home surface is up; entering a session re-decides
+      // through hideWelcome()/showWelcome() anyway, and before the first
+      // showWelcome() there is nothing on screen to swap.
+      if (this.activeSessionId) return;
+      const overlay = document.getElementById('welcomeOverlay');
+      const welcomeUp = !!overlay && overlay.classList.contains('visible');
+      if (!welcomeUp && !this.isMobileOverviewVisible()) return;
+      if (typeof this.showWelcome === 'function') this.showWelcome();
+    };
+    if (mq.addEventListener) mq.addEventListener('change', onChange);
+    else if (mq.addListener) mq.addListener(onChange);
   },
 
   _toggleMobileOverviewRunMenu() {