bundle JetBrains Mono for terminal panes

Vendor the 4 core weights (Regular, Italic, Bold, BoldItalic) of
JetBrains Mono v2.304 under app/assets/fonts/jetbrains_mono/, ~1 MB
total. OFL license checked in alongside. Declared as the
JetBrainsMono family in pubspec so Flutter bundles it automatically.

app/lib/widgets/src/typography.dart exposes clideMonoFamily plus a
platform-ordered fallback chain (SF Mono / Menlo / Monaco →
JetBrains Mono system install / Fira Code / Hack / DejaVu / Liberation →
Cascadia / Consolas → monospace) for web builds and test harnesses
that don't load asset fonts. Terminal widgets pick both up via a
single import.

Co-Authored-By: Claude <noreply@anthropic.com>

app/pubspec.yaml

@@ -53,3 +53,19 @@ flutter:
   assets:
     - lib/kernel/src/theme/themes/
     - lib/kernel/src/i18n/catalog/
+
+  # JetBrains Mono — bundled so terminal panes render consistently
+  # regardless of what the user has system-installed. OFL-licensed;
+  # see assets/fonts/jetbrains_mono/OFL.txt. Thin/Light/Medium/
+  # ExtraBold weights can be added later if a theme needs them.
+  fonts:
+    - family: JetBrainsMono
+      fonts:
+        - asset: assets/fonts/jetbrains_mono/JetBrainsMono-Regular.ttf
+        - asset: assets/fonts/jetbrains_mono/JetBrainsMono-Italic.ttf
+          style: italic
+        - asset: assets/fonts/jetbrains_mono/JetBrainsMono-Bold.ttf
+          weight: 700
+        - asset: assets/fonts/jetbrains_mono/JetBrainsMono-BoldItalic.ttf
+          weight: 700
+          style: italic