File-stability pre-sync guard + materials file-type icons

DESIGN.md

@@ -15,7 +15,9 @@ These rules are **never** overridden by component context, user request, or conv
 Agents must treat violations as hard errors.
 
 - **NEVER** use data colors (Okabe-Ito) for buttons, navigation, headings, text links,
-  input borders, or any UI chrome.
+  input borders, or any UI chrome. **Exception:** categorical file-type / node-type
+  icons (`ui/components/file_type_icon.py`, `tree._node_type_props`) may use `--oi-*`
+  hues -- they are a categorical *encoding* of a file/node category, not chrome.
 - **NEVER** use `#F0E442` (yellow) as text color, stroke, or thin line on white or light
   backgrounds.
 - **NEVER** render numeric data, axis labels, badge text, captions, or code outside
@@ -59,8 +61,11 @@ for data series.
 ### Data Colors -- Okabe-Ito -- Visualization Only
 
 Colorblind-safe palette designed by Masataka Okabe and Kei Ito. Safe across
-deuteranopia, protanopia, and tritanopia. Used **exclusively** for data visualization:
-plot series, progress bars, status badges, and semantic states.
+deuteranopia, protanopia, and tritanopia. Used for data visualization (plot
+series, progress bars, status badges, and semantic states) and for the
+**categorical file-type / node-type icon encoding** (`file_type_icon.py`,
+`tree._node_type_props`) -- a categorical encoding of a file/node category,
+not UI chrome.
 
 | Token            | Name           | Hex       | CB Safe     | Primary Use                 |
 |------------------|----------------|-----------|-------------|-----------------------------|

assets/fonts/mdi/LICENSE

@@ -0,0 +1,20 @@
+Pictogrammers Free License
+--------------------------
+
+This icon collection is released as free, open source, and GPL friendly by
+the [Pictogrammers](http://pictogrammers.com/) icon group. You may use it
+for commercial projects, open source projects, or anything really.
+
+# Icons: Apache 2.0 (https://www.apache.org/licenses/LICENSE-2.0)
+Some of the icons are redistributed under the Apache 2.0 license. All other
+icons are either redistributed under their respective licenses or are
+distributed under the Apache 2.0 license.
+
+# Fonts: Apache 2.0 (https://www.apache.org/licenses/LICENSE-2.0)
+All web and desktop fonts are distributed under the Apache 2.0 license. Web
+and desktop fonts contain some icons that are redistributed under the Apache
+2.0 license. All other icons are either redistributed under their respective
+licenses or are distributed under the Apache 2.0 license.
+
+# Code: MIT (https://opensource.org/licenses/MIT)
+The MIT license applies to all non-font and non-icon files.

assets/fonts/mdi/README.md

@@ -0,0 +1,39 @@
+# Vendored Material Design Icons (MDI) webfont
+
+The file-type / node-type icons (`ui/components/file_type_icon.py`,
+`ui/components/tree.py`) use Material Design Icons. NiceGUI/Quasar know the
+`mdi-*` icon names but do **not** bundle the MDI webfont, and this app ships as
+an offline PyInstaller desktop binary (no CDN), so the font must be vendored
+here. `ui/theme.py:mdi_font_head_html()` injects:
+
+    <link rel="stylesheet" href="/assets/fonts/mdi/css/materialdesignicons.min.css">
+
+served by `register_static_assets()` (mounts `assets/` at `/assets`). The whole
+`assets/` tree is already bundled by PyInstaller (`exlab_wizard.spec`:
+`DATAS.append(("assets", "assets"))`), so no spec change is needed once the
+files below are present.
+
+## Required files (place alongside this README)
+
+    assets/fonts/mdi/css/materialdesignicons.min.css
+    assets/fonts/mdi/fonts/materialdesignicons-webfont.woff2
+    assets/fonts/mdi/LICENSE          # Apache-2.0
+
+The `.min.css` references the woff2 via the relative `../fonts/...` URL, which
+resolves correctly under `/assets/fonts/mdi/`. Optionally trim the css
+`@font-face` `src` to the `woff2` entry to avoid 404s on the unbundled
+eot/ttf/woff formats.
+
+## How to fetch (on a networked machine)
+
+    npm pack @mdi/font@7
+    tar -xzf mdi-font-7.*.tgz
+    mkdir -p assets/fonts/mdi/css assets/fonts/mdi/fonts
+    cp package/css/materialdesignicons.min.css        assets/fonts/mdi/css/
+    cp package/fonts/materialdesignicons-webfont.woff2 assets/fonts/mdi/fonts/
+    cp package/LICENSE                                 assets/fonts/mdi/LICENSE
+
+(Or download those three files from the `@mdi/font` v7 GitHub release.)
+
+Until the font is present, the `<link>` 404s and glyphs render as empty boxes;
+the unit tests do not require the binary.