feat(settings): editor font size for chat input and code editor (#1325) (#2065)

* feat(settings): add editor font size setting for chat input and code editor

Adds an 'Editor font size' control in Settings > Appearance that sets an
absolute px font size for the chat input textarea and the in-app
CodeMirror editor. Mirrors the existing terminalFontSize lifecycle.

- New store field editorFontSize (default 13, clamp 9-32, step 1) in
  useUIStore with narrow selectors at each consumer.
- Persistence wired through appearanceAutoSave, desktop + runtime API
  types, and persistence.ts read/normalize.
- Settings UI row (NumberInput) with reset to 13, VisibleSetting union
  entry, OpenChamberPage registration, and search index entry
  appearance.editor-font-size.
- Applied as a post-zoom absolute override on the chat input textarea
  and on the CodeMirror theme's content rule, leaving gutter/line-number
  chrome at its existing hardcoded sizes (matches terminal scope).
- All 10 locales translated (en, es, fr, ja, ko, pl, pt-BR, uk, zh-CN,
  zh-TW); no English placeholders in non-English dictionaries.

Refs #1325

* fix(codemirror): use unitless lineHeight so it scales with editor font size

The & rule in the CodeMirror theme set lineHeight to 1.5rem (~24px),
which does not scale when editorFontSize is increased (e.g., 28-32px).
This causes overlapping lines at larger font sizes.

Change to unitless 1.5, which scales proportionally with whatever fontSize
resolves to (dynamic prop or --text-code fallback). Matches browser best
practice for proportional leading.

Review comment: https://github.com/openchamber/openchamber/pull/2065

---------

Co-authored-by: bashrusakh <bashrusakh@users.noreply.github.com>
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/ui/src/stores/useUIStore.ts

@@ -587,6 +587,7 @@ interface UIStore {
   // Global draft welcome starters; null = unset (use the default built-in set).
   globalDraftStarters: DraftStarterRef[] | null;
   terminalFontSize: number;
+  editorFontSize: number;
   uiFont: UiFontOption;
   monoFont: MonoFontOption;
   padding: number;
@@ -736,6 +737,7 @@ interface UIStore {
   setFontSize: (size: number) => void;
   setGlobalDraftStarters: (refs: DraftStarterRef[]) => void;
   setTerminalFontSize: (size: number) => void;
+  setEditorFontSize: (size: number) => void;
   setUiFont: (font: UiFontOption) => void;
   setMonoFont: (font: MonoFontOption) => void;
   setPadding: (size: number) => void;
@@ -883,6 +885,7 @@ export const useUIStore = create<UIStore>()(
         fontSize: 100,
         globalDraftStarters: null,
         terminalFontSize: 13,
+        editorFontSize: 13,
         uiFont: DEFAULT_UI_FONT,
         monoFont: DEFAULT_MONO_FONT,
         padding: 100,
@@ -1633,6 +1636,12 @@ export const useUIStore = create<UIStore>()(
           set({ terminalFontSize: clamped });
         },
 
+        setEditorFontSize: (size) => {
+          const rounded = Math.round(size);
+          const clamped = Math.max(9, Math.min(32, rounded));
+          set({ editorFontSize: clamped });
+        },
+
         setUiFont: (font) => {
           set({ uiFont: font });
         },
@@ -2279,6 +2288,7 @@ export const useUIStore = create<UIStore>()(
           fontSize: state.fontSize,
           globalDraftStarters: state.globalDraftStarters,
           terminalFontSize: state.terminalFontSize,
+          editorFontSize: state.editorFontSize,
           uiFont: state.uiFont,
           monoFont: state.monoFont,
           padding: state.padding,