Bugfix: Show "/" not a storage id in MTP-root tab titles

- The pane tab derived its title from the path basename, so at an MTP storage root the title surfaced the raw storage id (like `65537` = 0x10001 Internal Storage) instead of a sensible label.
- New `deriveTabLabel(path)` (`tabs/tab-label.ts`) special-cases the `mtp://` scheme: it derives the label from the within-storage path via `getMtpDisplayPath`, so a storage root shows "/" (matching the breadcrumb and the local filesystem root) and a subfolder shows its folder name. Mounted-volume roots (`/Volumes/USB`) keep their basename — only MTP is special-cased.
- Same disease the transfer-dialog header fix (`deriveTransferLabel`) already addressed; the tab is a separate consumer with the "/" convention the owner expects, so it gets its own helper rather than the dialog's display-name-at-root rule.

Author: vdavid

CHANGELOG.md

@@ -59,6 +59,7 @@ The format is based on [keep a changelog](https://keepachangelog.com/en/1.1.0/),
   ([f4a8b1cb](https://github.com/vdavid/cmdr/commit/f4a8b1cb))
 - Show the volume name instead of a raw storage id (like "65538") in the transfer dialog header
   ([f4a8b1cb](https://github.com/vdavid/cmdr/commit/f4a8b1cb))
+- Show "/" instead of a raw storage id (like "65537") in the tab title at a phone or camera storage root
 - Fix file viewer settings (word wrap, text size, binary warning) silently resetting every session
   ([51e127aa](https://github.com/vdavid/cmdr/commit/51e127aa))
 - Make the title bar draggable while a dialog is open, and in the file viewer window

apps/desktop/src/lib/file-explorer/tabs/CLAUDE.md

@@ -9,6 +9,10 @@ Per-pane tab system for the dual-pane file explorer. Each pane side (left/right)
   pin). Max 10 tabs per pane.
 - `TabBar.svelte`: Tab bar UI component. Always visible, Chrome-style shrinking tabs, pin icons, close buttons, context
   menu.
+- `tab-label.ts`: `deriveTabLabel(path)` — the tab title. Basename via `getFolderName` for normal paths, but for an MTP
+  path (`mtp://…`) it derives from the within-storage path (`getMtpDisplayPath`) so the storage root shows "/" instead
+  of the raw storage id (`65537`). Mounted-volume roots (`/Volumes/USB`) keep their basename; only the MTP scheme is
+  special-cased. Pinned by `tab-label.test.ts`.
 - `tab-state-manager.test.ts`: Unit tests for state manager
 
 ## Key decisions

apps/desktop/src/lib/file-explorer/tabs/TabBar.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
     import type { TabState, TabId } from './tab-types'
     import { tooltip } from '$lib/tooltip/tooltip'
-    import { getFolderName } from '$lib/file-operations/transfer/transfer-dialog-utils'
+    import { deriveTabLabel } from './tab-label'
     import { getVolumes } from '$lib/stores/volume-store.svelte'
 
     interface Props {
@@ -132,7 +132,7 @@
                     </span>
                 {/if}
                 <span class="tab-label">
-                    {getFolderName(tab.path)}
+                    {deriveTabLabel(tab.path)}
                 </span>
                 {#if !isSingleTab}
                     <span

apps/desktop/src/lib/file-explorer/tabs/tab-label.test.ts

@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest'
+import { deriveTabLabel } from './tab-label'
+
+describe('deriveTabLabel', () => {
+  it('shows "/" at an MTP storage root instead of the raw storage id', () => {
+    // At the MTP storage root the last path segment is the raw storage id
+    // (here 65537 = 0x10001 for Internal Storage), which used to surface as
+    // the tab title "65537". A storage root carries no user-meaningful
+    // basename, so the tab shows "/" — the same thing a local filesystem
+    // root shows.
+    expect(deriveTabLabel('mtp://0-5/65537')).toBe('/')
+  })
+
+  it('shows the folder name for an MTP subfolder', () => {
+    expect(deriveTabLabel('mtp://0-5/65537/DCIM/Camera')).toBe('Camera')
+    expect(deriveTabLabel('mtp://0-5/65537/DCIM')).toBe('DCIM')
+  })
+
+  it('shows "/" for the local filesystem root (convention pinned)', () => {
+    expect(deriveTabLabel('/')).toBe('/')
+  })
+
+  it('shows the basename for a local subfolder (convention pinned)', () => {
+    expect(deriveTabLabel('/Users/john/Documents')).toBe('Documents')
+  })
+
+  it('shows the volume folder name for a mounted-volume root (convention pinned)', () => {
+    // A mounted volume root like /Volumes/USB keeps its basename ("USB"),
+    // unchanged from the local convention — we only special-case the MTP
+    // storage root, not every volume root.
+    expect(deriveTabLabel('/Volumes/USB')).toBe('USB')
+  })
+})

apps/desktop/src/lib/file-explorer/tabs/tab-label.ts

@@ -0,0 +1,26 @@
+import { getFolderName } from '$lib/file-operations/transfer/transfer-dialog-utils'
+import { getMtpDisplayPath } from '$lib/mtp'
+
+/**
+ * Derives the user-facing label for a tab from its path.
+ *
+ * Normally the basename is the right thing to show ("Documents" for
+ * `/Users/john/Documents`, "/" for the local filesystem root). But an MTP path
+ * (`mtp://{deviceId}/{storageId}/inner/path`) puts the raw storage id as the
+ * last segment at the storage root, which surfaced as the tab title "65537"
+ * (0x10001 = Internal Storage). For MTP paths we derive the label from the
+ * inner (within-storage) path instead: "/" at the storage root, the inner
+ * folder basename below it — matching what the breadcrumb already shows.
+ *
+ * We special-case ONLY the MTP scheme. Every other path (including mounted
+ * volume roots like `/Volumes/USB`, which keep their basename "USB") flows
+ * through `getFolderName` unchanged.
+ */
+export function deriveTabLabel(path: string): string {
+  if (path.startsWith('mtp://')) {
+    // `getMtpDisplayPath` returns "/" at the storage root and `/DCIM/Camera`
+    // for a subfolder; its basename is the tab label.
+    return getFolderName(getMtpDisplayPath(path))
+  }
+  return getFolderName(path)
+}