New mobile layout, new regular screen, added the ability to edit directory names from settings

OfflineU-project-summary.md

@@ -97,6 +97,32 @@ built locally from a private Gitea repo rather than pulling the upstream image.
   official palette (nordtheme.com). Anyone with `theme: "dainty"` already saved
   in `settings.json` falls back gracefully to the `dark` default on next load.
 
+## Mobile UI overhaul + in-app renaming (this session)
+- **Fixed the mobile text-overlap bug** — `.lesson-item`/`.tree-header` in
+  `course_dashboard.html` had no `min-width: 0` or truncation on their flex
+  children, so long course/lesson names (especially scene-release-style dotted
+  names like `Udemy.crash.course.electronics...Mimir` with zero whitespace to
+  wrap on) would overflow and visually overlap neighboring text on narrow
+  screens. Fixed with `min-width:0` + ellipsis truncation (desktop/tablet) and
+  a `@media (max-width: 600px)` block that stacks title/metadata into separate
+  lines with `overflow-wrap: break-word` (the dotted-name case needed this
+  specifically — plain `white-space: normal` doesn't create a break opportunity
+  in a string with no spaces).
+- **Library browser redesigned** — replaced the nested-indent accordion
+  (`AI` → `ChatGPT` → course, each level eating horizontal space) with a
+  single-level drill-down + breadcrumb (`Library / AI / ChatGPT`), the standard
+  mobile file-browser pattern. Tapping a folder now replaces the list instead
+  of nesting under it. In-course lesson tree keeps its old expand-in-place
+  behavior (shallower, wasn't the reported problem).
+- **Rename courses/folders from Settings** — "Curate Library" is now
+  "Manage Library": each row gets a ✏️ button alongside Hide/Show that renames
+  the directory in place on disk via a new `POST /api/rename-path`. Handles
+  path-traversal/collision validation, and rebases any `hidden_paths.json` /
+  `recent_views.json` entries nested under the renamed path (progress files
+  need no rebasing — they live inside the directory and are keyed relative to
+  it). If you rename your *currently loaded* course's folder, the app resets
+  to the library view rather than serving a stale path.
+
 ## Known limitations still open
 - App is unauthenticated by design (matches upstream) — settings and hidden-path
   curation apply app-wide, not per-browser/per-user.