Onboarding: push failed listings to nav history; cleaner restricted-folder icons

- `FilePane.svelte` now pushes the path to navigation history on listing error too,
  not only on `listing-complete`. Without this, navigating to a TCC-restricted folder
  showed the `ErrorPane` but left the path missing from history — Cmd+[ then jumped
  back two visual steps instead of one. `pushPath` deduplicates same-path retries, so
  hammering "Try again" doesn't bloat the stack.
- `VolumeBreadcrumb.svelte` falls back to the generic Aqua folder icon (the cached
  `dir` icon) for sidebar entries whose path is in the TCC-restricted set, both in the
  closed breadcrumb and dropdown rows. `NSWorkspace.iconForFile:` on a TCC-denied path
  returns a confusing "no access" placeholder; preferring the generic folder icon
  keeps the favorites visually consistent with the rest of the sidebar.

Author: vdavid

apps/desktop/src/lib/file-explorer/navigation/VolumeBreadcrumb.svelte

@@ -483,7 +483,11 @@
     <!-- svelte-ignore a11y_click_events_have_key_events -->
     <!-- svelte-ignore a11y_no_static_element_interactions -->
     <span class="volume-name" class:is-open={isOpen} onclick={handleToggle}>
-        {#if currentVolumeIcon}
+        {#if currentVolume && isRestricted(currentVolume.path) && dirIconFallback}
+            <!-- TCC-denied paths: `NSWorkspace.iconForFile` returns a confusing "no
+                 access" placeholder. Use the generic Aqua folder icon instead. -->
+            <img class="icon" src={dirIconFallback} alt="" />
+        {:else if currentVolumeIcon}
             <img class="icon" src={currentVolumeIcon} alt="" />
         {:else if volumeId === 'network'}
             <span class="icon-emoji">🌐</span>
@@ -579,6 +583,10 @@
                             <img class="volume-icon" src="/icons/mobile-device.svg" alt="" />
                         {:else if volume.category === 'network'}
                             <span class="volume-icon-placeholder">🌐</span>
+                        {:else if isRestricted(volume.path) && dirIconFallback}
+                            <!-- TCC-denied paths: `NSWorkspace.iconForFile` returns a confusing "no
+                                 access" placeholder. Use the generic Aqua folder icon instead. -->
+                            <img class="volume-icon" src={dirIconFallback} alt="" />
                         {:else if volume.icon}
                             <img class="volume-icon" src={volume.icon} alt="" />
                         {:else if dirIconFallback}

apps/desktop/src/lib/file-explorer/pane/FilePane.svelte

@@ -1030,6 +1030,12 @@
                             } else {
                                 // Path exists, or we couldn't tell — show the original listing error
                                 resetLoadingState(event.payload.message, false, event.payload.friendly)
+                                // Record the failed path in history so Cmd+[ goes back one step,
+                                // not two. The success path pushes via the `onPathChange` call in
+                                // `handleListingComplete`; without this call, an error pane would
+                                // be visually displayed but absent from history, so Back would
+                                // skip over it. `pushPath` deduplicates same-path retries.
+                                onPathChange?.(loadPath)
                             }
                         })
                     }