fix(mobile): raise the phone breakpoint from 430px to 600px

The phone tier stopped at innerWidth < 430 and @media (max-width: 430px), so every current large phone landed in the tablet layout: the 430pt iPhone 14 Pro Max, 15 Plus, 15 Pro Max and 16 Plus, the 440pt iPhone 16 Pro Max and 17 Pro Max, Pixel 6 Pro, 7 Pro and OnePlus 12 Pro, the 448pt Pixel 8 Pro and 9 Pro XL, and the Galaxy Z Fold 5 cover screen at 460. On those devices the header icon row replaced the session pill, the toolbar kept the desktop Run Shell button instead of Enter and the mic, the keyboard accessory bar could never become visible because its .visible rule lives inside the phone block, and the toolbar jumped to the top of the page when the keyboard opened.

The new cutoff is 600, the line test/mobile/devices.ts already draws between large phones (430-599) and small tablets (600-767). No physical device sits between 480 and 600, but a phone zoomed out one or two steps in Safari does: a 440pt iPhone at 85% or 75% page zoom reports 518px or 587px and still needs the phone controls, which a 480 cutoff would have taken away. The phone block is max-width: 599px and the tablet block starts at min-width: 600px, so a 600px device is a tablet in CSS and in getDeviceType() alike instead of straddling the boundary the way 430pt phones did.

The number changes everywhere it is encoded: JS, CSS, comments, CLAUDE.md, the CI tests that pin the phone block, and the test:mobile helpers. Measurement history that names 430px stays as written.

src/web/public/index.html

@@ -686,7 +686,7 @@
           <button class="btn-toolbar btn-shell" onclick="app.runShell()" title="Run Shell">
             Run Shell
           </button>
-          <!-- Phone-only: replaces the Shell button on ≤430px (Shell moves into the Run
+          <!-- Phone-only: replaces the Shell button under 600px (Shell moves into the Run
                dropdown there). Sends a bare Enter to the active session, the complement
                to the accessory bar's Esc. Hidden everywhere else — see styles.css. -->
           <button class="btn-toolbar btn-enter" onclick="app.sendEnterKey()" title="Send Enter">

src/web/public/mobile-handlers.js

@@ -85,20 +85,20 @@ const MobileDetection = {
     return /^((?!chrome|android).)*safari/i.test(navigator.userAgent);
   },
 
-  /** Check if screen is small (phone-sized, <430px) */
+  /** Check if screen is small (phone-sized, <600px) */
   isSmallScreen() {
-    return window.innerWidth < 430;
+    return window.innerWidth < 600;
   },
 
-  /** Check if screen is medium (tablet-sized, 430-768px) */
+  /** Check if screen is medium (tablet-sized, 600-768px) */
   isMediumScreen() {
-    return window.innerWidth >= 430 && window.innerWidth < 768;
+    return window.innerWidth >= 600 && window.innerWidth < 768;
   },
 
   /** Get device type based on screen width */
   getDeviceType() {
     const width = window.innerWidth;
-    if (width < 430) return 'mobile';
+    if (width < 600) return 'mobile';
     if (width < 768) return 'tablet';
     return 'desktop';
   },

src/web/public/mobile-overview.js

@@ -12,7 +12,7 @@
  * the SAME comparator the desktop rail uses: blocked longest-first, then
  * running longest-first, then quiet most-recently-quiet first.
  *
- * PHONE ONLY. The gate is `shouldUseMobileOverview()` (viewport < 430px, not a
+ * PHONE ONLY. The gate is `shouldUseMobileOverview()` (viewport < 600px, not a
  * popped-out solo window, per-device setting on). Tablet and desktop keep the
  * welcome overlay untouched. The container ships with the `hidden` attribute and
  * only this module removes it, so desktop (which never loads mobile.css) cannot
@@ -38,7 +38,7 @@
  */
 
 /** Viewport width that counts as a phone. Matches the mobile.css phone block. */
-const MOBILE_OVERVIEW_PHONE_QUERY = '(max-width: 430px)';
+const MOBILE_OVERVIEW_PHONE_QUERY = '(max-width: 599px)';
 
 /** How many past conversations show before the "Show all" toggle. */
 const MOBILE_OVERVIEW_PAST_LIMIT = 8;

src/web/public/mobile.css

@@ -46,9 +46,9 @@ html.mobile-init .file-browser-panel {
 }
 
 /* ============================================================================
-   Tablet Breakpoint (430px - 768px)
+   Tablet Breakpoint (600px - 768px)
    ============================================================================ */
-@media (max-width: 768px) and (min-width: 430px) {
+@media (max-width: 768px) and (min-width: 600px) {
   /* Compact header for tablet - fixed at top, includes safe area padding */
   .header {
     position: fixed;
@@ -303,12 +303,12 @@ html.mobile-init .file-browser-panel {
   }
 
   /* Show desktop voice button on tablet (hidden by max-width:1023px in styles.css,
-     mobile .btn-voice-mobile only shows at <430px) */
+     mobile .btn-voice-mobile only shows at <600px) */
   .toolbar-center .btn-toolbar.btn-voice {
     display: flex !important;
   }
 
-  /* Toolbar — use desktop-style sizing on tablet (plenty of room at 430-768px) */
+  /* Toolbar — use desktop-style sizing on tablet (plenty of room at 600-768px) */
   .toolbar {
     padding: 0 0.5rem;
     gap: 0.5rem;
@@ -333,9 +333,9 @@ html.mobile-init .file-browser-panel {
 }
 
 /* ============================================================================
-   Phone Breakpoint (<430px)
+   Phone Breakpoint (<600px)
    ============================================================================ */
-@media (max-width: 430px) {
+@media (max-width: 599px) {
   /* Phones get a 44px header, up from 36px. Every header control is a touch
      target and 44px is the floor for one; the brand "C" that gets you home is
      the one that matters most. Redefined as the TOKEN rather than a literal so
@@ -499,7 +499,7 @@ html.mobile-init .file-browser-panel {
 
   /* Exception to the 26px shrink above: in sidebar layout this button is the
      ONLY way to open the session list — the strip it replaced is gone. A 26px
-     target is below --touch-target-min (44px), which the 430-768px block
+     target is below --touch-target-min (44px), which the 600-768px block
      already enforces for every other header button. */
   html[data-session-list='sidebar'] #sidebarToggleBtn {
     width: 44px;
@@ -1167,7 +1167,7 @@ html.mobile-init .file-browser-panel {
     }
   }
 
-  @media (max-width: 430px) {
+  @media (max-width: 599px) {
     .btn-case-settings-mobile {
       display: none !important;
     }
@@ -3144,7 +3144,7 @@ html:is([data-skin="paper-gray"], [data-skin="solarized-light"], [data-skin="cat
 
 /* Keyboard accessory bar + paste overlay base styles moved to styles.css
    (always loaded — covers iPad landscape where mobile.css doesn't load).
-   Phone-specific overrides remain in @media (max-width: 430px) above. */
+   Phone-specific overrides remain in @media (max-width: 599px) above. */
 
 /* ============================================================================
    iOS Safari Specific Fixes
@@ -3187,7 +3187,7 @@ html:is([data-skin="paper-gray"], [data-skin="solarized-light"], [data-skin="cat
   }
 }
 
-@media (max-width: 430px) {
+@media (max-width: 599px) {
   /* Attachment history (COD-18): full-screen sheet on phones */
   .attachment-history-drawer {
     top: 0;
@@ -3237,7 +3237,7 @@ html:is([data-skin="paper-gray"], [data-skin="solarized-light"], [data-skin="cat
    already reserves that space), so it needs the same safe-area padding as the
    other banners. The overlay is fixed and handles its own insets.
    ============================================================================ */
-@media (max-width: 430px) {
+@media (max-width: 599px) {
   .offline-banner {
     padding: 0.4rem 0.5rem;
     padding-left: calc(0.5rem + var(--safe-area-left));
@@ -3727,7 +3727,7 @@ html:is([data-skin="paper-gray"], [data-skin="solarized-light"], [data-skin="cat
    This whole file is served with media="(max-width: 1023px)", so these
    top-level rules cover the entire handheld range — deliberately NOT wrapped in
    a nested @media, because the two compact `.session-tabs` blocks above live in
-   `max-width: 768px` and `max-width: 430px` and would leave 769-1023px
+   `max-width: 768px` and `max-width: 599px` and would leave 769-1023px
    unhandled.
 
    Placement at the END of the file is load-bearing: the compact strip blocks at

src/web/public/session-ui.js

@@ -2526,7 +2526,7 @@ Object.assign(CodemanApp.prototype, {
       if (!input._mobileScrollWired) {
         input._mobileScrollWired = true;
         input.addEventListener('focus', () => {
-          if (window.innerWidth <= 430) {
+          if (window.innerWidth < 600) {
             setTimeout(() => input.scrollIntoView({ behavior: 'smooth', block: 'center' }), 300);
           }
         });

src/web/public/settings-ui.js

@@ -376,7 +376,7 @@ Object.assign(CodemanApp.prototype, {
     document.getElementById('appSettingsShowMultiMonitorButton').checked = settings.showMultiMonitorButton ?? defaults.showMultiMonitorButton ?? false;
     document.getElementById('appSettingsShowPlanUsageLimits').checked = this.planUsageChipEnabled(settings);
     document.getElementById('appSettingsShowRedrawButton').checked = settings.showRedrawButton ?? defaults.showRedrawButton ?? false;
-    // Phone overview home screen: only meaningful under 430px, so the row is
+    // Phone overview home screen: only meaningful under 600px, so the row is
     // hidden elsewhere rather than offering a toggle that changes nothing.
     // Spawn lineage lines: desktop-only (the overlay sits UNDER the fixed mobile
     // header), so the row is hidden elsewhere rather than offering a toggle that

src/web/public/styles.css

@@ -5156,7 +5156,7 @@ body.touch-device .terminal-container .xterm .xterm-helper-textarea {
 .run-mode-dot.shell { background: #94a3b8; }
 
 /* Phone-only Enter button (see index.html). Hidden by default at every width;
-   mobile.css turns it on inside @media (max-width: 430px), where it takes over
+   mobile.css turns it on inside @media (max-width: 599px), where it takes over
    the slot the Shell button occupies on wider screens. */
 .btn-toolbar.btn-enter {
   display: none;
@@ -11807,7 +11807,7 @@ kbd {
 }
 /* Footer row: the buttons are btn-toolbar (display: flex, block-level), so
    without this rule the four of them stack vertically. Mirrors the
-   runSummaryModal footer; the ≤430px block in mobile.css adds wrapping. */
+   runSummaryModal footer; the phone block (under 600px) in mobile.css adds wrapping. */
 .readmymind-modal .modal-footer {
   display: flex;
   justify-content: flex-end;
@@ -13184,7 +13184,7 @@ body.touch-device.cjk-input-visible .main {
    Keyboard Accessory Bar
    Base styles in styles.css (always loaded) so iPad landscape (≥1024px,
    where mobile.css doesn't load) still gets dark styling. Phone overrides
-   remain in mobile.css @media (max-width: 430px).
+   remain in mobile.css @media (max-width: 599px).
    ═══════════════════════════════════════════════════════════════ */
 
 .keyboard-accessory-bar {

src/web/public/terminal-ui.js

@@ -4842,7 +4842,7 @@ Object.assign(CodemanApp.prototype, {
     const viewportType =
       typeof MobileDetection !== 'undefined' && MobileDetection.getDeviceType
         ? MobileDetection.getDeviceType()
-        : window.innerWidth < 430
+        : window.innerWidth < 600
           ? 'mobile'
           : window.innerWidth < 768
             ? 'tablet'