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/components/chat/ChatInput.tsx

@@ -1121,6 +1121,7 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
     const inputBarOffset = useUIStore((state) => state.inputBarOffset);
     const persistChatDraft = useUIStore((state) => state.persistChatDraft);
     const inputSpellcheckEnabled = useUIStore((state) => state.inputSpellcheckEnabled);
+    const editorFontSize = useUIStore((state) => state.editorFontSize);
     const isExpandedInput = useUIStore((state) => state.isExpandedInput);
     const setExpandedInput = useUIStore((state) => state.setExpandedInput);
     const setTimelineDialogOpen = useUIStore((state) => state.setTimelineDialogOpen);
@@ -5256,6 +5257,7 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
                                     maxHeight: !isComposerExpanded && textareaSize ? `${textareaSize.maxHeight}px` : undefined,
                                     borderTopLeftRadius: chatInputRadius,
                                     borderTopRightRadius: chatInputRadius,
+                                    fontSize: `${editorFontSize}px`,
                                 }}
                                 rows={1}
                             />