feat(i18n): Hebrew locale + full RTL support (#243)

# feat(i18n): Hebrew locale + full RTL support

## Summary

This PR adds full Hebrew (he) locale support to the UI, including a
complete translation of all user-facing strings and comprehensive RTL
layout support across all components.

## What was done

### Hebrew translation
- Full translation of all i18n message files for the `he` locale (17
translation files)
- Registered the language in the i18n system and the language picker

### RTL support
- Automatic direction detection (`dir="rtl"`) when Hebrew is selected
- Replaced physical CSS properties (`left`/`right`) with logical
equivalents (`inline-start`/`inline-end`) across the project
- Fixed resize direction, file path alignment, and textarea padding
- Fixed navigation button positioning in textarea for RTL
- Fixed scrollbar direction in RTL
- Fixed code block direction and selector alignment
- Fixed Monaco editor direction in the file viewer
- Auto-detect text direction in reasoning block (`dir="auto"` +
`unicode-bidi: plaintext`)

### Adapted components
- `session-layout` — sidebar and resize handle
- `prompt-input` — text direction and buttons
- `message-base` — message blocks and reasoning
- `message-timeline` — timeline bar
- `right-panel` — right side panel
- `tool-call` — tool call display
- `settings-screen` — settings page
- `selector` — selection component
- `instance-shell` — main shell

## New files

```
packages/ui/src/lib/i18n/messages/he/
  advancedSettings.ts
  app.ts
  commands.ts
  dialogs.ts
  filesystem.ts
  folderSelection.ts
  index.ts
  instance.ts
  loadingScreen.ts
  logs.ts
  markdown.ts
  messaging.ts
  remoteAccess.ts
  session.ts
  settings.ts
  time.ts
  toolCall.ts
```

## Suggested testing
- Switch language to Hebrew and verify all strings are translated
- Verify RTL layout is correct across all screens (session, settings,
file viewer)
- Verify that English text inside a reasoning block is displayed LTR
- Switch back to English and verify everything returns to LTR

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Shantur Rathore <i@shantur.com>

packages/ui/src/lib/i18n/messages/en/instance.ts

@@ -114,6 +114,7 @@ export const instanceMessages = {
   "instanceShell.sessionChanges.filesChanged": "{count} files changed",
   "instanceShell.sessionChanges.actions.show": "Show changes",
 
+  "instanceShell.gitChanges.noSessionSelected": "Select a session to view git changes.",
   "instanceShell.gitChanges.loading": "Loading git changes...",
   "instanceShell.gitChanges.empty": "No git changes yet.",
   "instanceShell.gitChanges.deleted": "Deleted",
@@ -124,6 +125,15 @@ export const instanceMessages = {
   "instanceShell.filesShell.viewerTitle": "Change viewer",
   "instanceShell.filesShell.viewerPlaceholder": "Detailed change rendering will be added in the next step.",
   "instanceShell.filesShell.viewerEmpty": "No file selected.",
+  "instanceShell.filesShell.hideFiles": "Hide files",
+  "instanceShell.filesShell.showFiles": "Show files",
+  "instanceShell.diff.hideUnchanged": "Hide unchanged regions",
+  "instanceShell.diff.showFull": "Show full file",
+  "instanceShell.diff.switchToSplit": "Switch to split view",
+  "instanceShell.diff.switchToUnified": "Switch to unified view",
+  "instanceShell.diff.enableWordWrap": "Enable word wrap",
+  "instanceShell.diff.disableWordWrap": "Disable word wrap",
+  "instanceShell.worktree.create": "+ Create worktree",
 
   "instanceShell.plan.noSessionSelected": "Select a session to view plan.",
   "instanceShell.plan.empty": "Nothing planned yet.",