docker: address second-round review feedback on the JupyterLab/Studio UX

- studio_launch.sh: also gate the categorized-view landing URL on
  UNSLOTH_SKIP_NOTEBOOK_SYNC (the entrypoint skips building the view entirely in
  that mode), not just UNSLOTH_SKIP_NOTEBOOK_VIEW, so a no-sync container does not
  land on a missing folder.

- Dockerfile.studio: scope the sticker-install "|| echo" fallback to only the
  sticker step via a { ...; } group. It was attached to the whole branding &&
  chain, so a failure in a REQUIRED step (JS resolve, favicon/logo/login copy)
  was swallowed and the build continued with broken branding.

- unsloth_nb_view.py: when creating the categorized symlinks, only replace our
  own stale symlinks; if a real user file already occupies that name, keep it and
  skip the link instead of os.remove-ing it.

- overrides.json: drop doNotDisturbMode (it silenced ALL JupyterLab toasts,
  including kernel-restart / connection-drop feedback). The news/update prompts
  are already off via fetchNews / checkForUpdates.

- Dockerfile: keep decord mandatory on amd64 (fail the build on a missing or
  incompatible wheel) and only fail-soft on arm64/other arches that have no wheel.

- cellNav.ts: do not hijack ArrowUp/Down when focus is in an interactive output
  widget / form control, or while a completion popup is open, so ipywidgets
  controls and autocomplete at cell boundaries keep working.

docker/Dockerfile

@@ -303,11 +303,16 @@ RUN ${VENV}/bin/uv pip install \
         "omegaconf==2.3.1" "einx==0.4.3" "librosa==0.11.0" "ftfy==6.3.1" \
  && ${VENV}/bin/python -c "import torch, numpy, numba; from packaging.version import Version; assert torch.__version__.startswith('2.10.0'), torch.__version__; assert Version(numpy.__version__) >= Version('2.3'), numpy.__version__; assert Version(numba.__version__) >= Version('0.65'), numba.__version__; print('notebook-deps pins OK:', torch.__version__, numpy.__version__, numba.__version__)"
 
-# decord (ERNIE-VL video decode) publishes wheels only for x86_64 / win_amd64,
-# so install it on its own and fail-soft: amd64 gets it; on arm64 the ERNIE-VL
-# video path is skipped rather than breaking the whole image build.
-RUN ${VENV}/bin/uv pip install --python ${VENV}/bin/python "decord==0.6.0" \
- || echo ">> decord skipped (no matching wheel for ${TARGETARCH:-amd64}); ERNIE-VL video decode unavailable"
+# decord (ERNIE-VL video decode) publishes wheels only for x86_64 / win_amd64.
+# Install it on its own: HARD on amd64 (a missing/incompatible wheel is a real
+# regression there and must fail the build), fail-soft on arm64/other (no wheel
+# exists, so drop the ERNIE-VL video path rather than break the image build).
+RUN if [ "${TARGETARCH:-amd64}" = "amd64" ]; then \
+        ${VENV}/bin/uv pip install --python ${VENV}/bin/python "decord==0.6.0"; \
+    else \
+        ${VENV}/bin/uv pip install --python ${VENV}/bin/python "decord==0.6.0" \
+        || echo ">> decord skipped (no matching wheel for ${TARGETARCH:-}); ERNIE-VL video decode unavailable"; \
+    fi
 
 # Audio decode out of the box: the TTS/STT notebooks feed datasets' Audio
 # features, which decode through torchcodec. Three traps, all defended:

docker/Dockerfile.studio

@@ -220,12 +220,15 @@ RUN JS="$(/opt/unsloth-venv/bin/python -c 'import os, jupyter_server; print(os.p
  && cp /tmp/unsloth-branding/logo.png "${JS}/static/logo/logo.png" \
  && cp /tmp/unsloth-branding/login.html "${JS}/templates/login.html" \
     # Copy the curated Studio sloth stickers the login page rotates through into
-    # jupyter_server's static dir (sloth/NN.png). Fail-soft: if the Studio
-    # public folder ever moves, login.html's onerror falls back to the logo.
- && /opt/unsloth-venv/bin/python /tmp/unsloth-branding/install_sloth_stickers.py \
+    # jupyter_server's static dir (sloth/NN.png). Fail-soft -- but scoped to ONLY
+    # the sticker step via the { ...; } group so a failure in a REQUIRED branding
+    # step above (JS resolve, favicon/logo/login copy) still fails the build
+    # instead of being swallowed by this fallback. If the Studio public folder
+    # ever moves, login.html's onerror falls back to the logo.
+ && { /opt/unsloth-venv/bin/python /tmp/unsloth-branding/install_sloth_stickers.py \
         --src "${UNSLOTH_STUDIO_HOME}/src/studio/frontend/public/Sloth emojis" \
         --dest "${JS}/static/sloth" \
-    || echo ">> sloth stickers not installed (login falls back to the Unsloth logo)" \
+      || echo ">> sloth stickers not installed (login falls back to the Unsloth logo)"; } \
  && rm -rf /tmp/unsloth-branding \
  && /opt/unsloth-venv/bin/jupyter labextension disable @jupyterlab/application-extension:logo \
  && /opt/unsloth-venv/bin/jupyter labextension lock @jupyterlab/application-extension:logo

docker/jupyter/overrides.json

@@ -35,7 +35,6 @@
   },
   "@jupyterlab/apputils-extension:notification": {
     "fetchNews": "false",
-    "checkForUpdates": false,
-    "doNotDisturbMode": true
+    "checkForUpdates": false
   }
 }

docker/jupyter/unsloth_labext/src/cellNav.ts

@@ -41,6 +41,19 @@ const cellNavPlugin: JupyterFrontEndPlugin<void> = {
       if (!panel.node.contains(event.target as Node)) {
         return;
       }
+      // Never hijack arrows that belong to an interactive output (an ipywidgets
+      // slider / dropdown / text box created by a cell) or a plain form control;
+      // only the cell editor and the notebook's own command-mode cell nav.
+      const targetEl = event.target as HTMLElement | null;
+      if (targetEl) {
+        if (targetEl.closest('.jp-OutputArea')) {
+          return;
+        }
+        const tag = targetEl.tagName;
+        if (tag === 'INPUT' || tag === 'TEXTAREA' || tag === 'SELECT') {
+          return;
+        }
+      }
       const notebook = panel.content;
       const direction = event.key === 'ArrowDown' ? 1 : -1;
       const editing = notebook.mode === 'edit';
@@ -49,6 +62,16 @@ const cellNavPlugin: JupyterFrontEndPlugin<void> = {
         if (!editor) {
           return;
         }
+        // While a completion / autocomplete popup is open, the arrows belong to
+        // it (moving through the suggestions) -- do not take over even at a cell
+        // boundary, which is common in one-line setup cells.
+        if (
+          document.querySelector(
+            '.jp-Completer:not(.lm-mod-hidden), .cm-tooltip-autocomplete'
+          )
+        ) {
+          return;
+        }
         const line = editor.getCursorPosition().line;
         // Only take over at the cell boundary; otherwise let CodeMirror move the
         // cursor within the editor as usual (do not preventDefault/stop).

docker/studio_launch.sh

@@ -65,12 +65,16 @@ c.PasswordIdentityProvider.hashed_password = "${HASH}"
 EOF
     # Land straight in the categorized notebook view, but only when it is enabled
     # AND lives under root_dir (so it is expressible as a /lab/tree path). Mirror
-    # unsloth_sync_notebooks.sh's UNSLOTH_NOTEBOOKS_VIEW_DIR / UNSLOTH_SKIP_NOTEBOOK_VIEW
-    # so a relocated or disabled view never points JupyterLab at a missing dir;
-    # in those cases JupyterLab just opens on its default (/lab) over /workspace.
+    # unsloth_sync_notebooks.sh's gating -- UNSLOTH_NOTEBOOKS_VIEW_DIR plus both
+    # UNSLOTH_SKIP_NOTEBOOK_VIEW (no view built) and UNSLOTH_SKIP_NOTEBOOK_SYNC
+    # (entrypoint skips sync entirely, so nothing under the view dir exists) -- so
+    # a relocated, disabled, or unsynced view never points JupyterLab at a missing
+    # dir; in those cases JupyterLab just opens on its default (/lab) over /workspace.
     _root_dir="/workspace"
     _view_dir="${UNSLOTH_NOTEBOOKS_VIEW_DIR:-/workspace/Unsloth Notebooks}"
-    if [[ "${UNSLOTH_SKIP_NOTEBOOK_VIEW:-0}" != "1" && "${_view_dir}" == "${_root_dir}/"* ]]; then
+    if [[ "${UNSLOTH_SKIP_NOTEBOOK_VIEW:-0}" != "1" \
+          && "${UNSLOTH_SKIP_NOTEBOOK_SYNC:-0}" != "1" \
+          && "${_view_dir}" == "${_root_dir}/"* ]]; then
         _view_rel="${_view_dir#${_root_dir}/}"
         # default_url must be set on BOTH ServerApp and LabApp -- the lab
         # extension app otherwise overrides ServerApp's value back to /lab.

docker/unsloth_nb_view.py

@@ -155,8 +155,14 @@ def build_view(
             target = os.path.join(nb_dir, fname)
             rel = os.path.relpath(target, folder)  # ../../unsloth-notebooks/nb/<file>
             try:
-                if os.path.islink(link) or os.path.exists(link):
-                    os.remove(link)
+                if os.path.islink(link):
+                    os.remove(link)          # replace our own stale symlink
+                elif os.path.exists(link):
+                    # a real user file/dir already occupies this name -- never
+                    # clobber it; leave it and skip linking this notebook.
+                    print(f"[unsloth-nb] view: keep user file, skip link {fname}",
+                          file = sys.stderr)
+                    continue
                 os.symlink(rel, link)
                 n_links += 1
             except OSError as e: