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/styles/messaging/prompt-input.css

@@ -35,7 +35,9 @@
 }
 
 .prompt-input {
-  @apply w-full pl-3 pr-10 pt-2.5 border text-sm resize-none outline-none transition-colors;
+  @apply w-full pt-2.5 border text-sm resize-none outline-none transition-colors;
+  padding-inline-start: 2.5rem;
+  padding-inline-end: 0.75rem;
   font-family: inherit;
   background-color: var(--surface-base);
   color: var(--text-primary);
@@ -65,8 +67,8 @@
 .prompt-input-overlay {
   position: absolute;
   bottom: 1rem;
-  left: 0.75rem;
-  right: 0.75rem;
+  inset-inline-start: 0.75rem;
+  inset-inline-end: 0.75rem;
   display: flex;
   flex-wrap: wrap;
   gap: 0.5rem;
@@ -81,11 +83,13 @@
   color: var(--text-primary);
 }
 
-/* Navigation buttons container (expand, prev, next) */
+/* Navigation buttons container (expand, prev, next).
+   Intentionally at inline-start (left in LTR, right in RTL) so buttons never overlap
+   the scrollbar, which browsers always place at inline-end. */
 .prompt-nav-buttons {
   position: absolute;
   top: 0.25rem;
-  right: 0.25rem;
+  inset-inline-start: 0.25rem;
   bottom: 0.25rem;
   display: flex;
   flex-direction: column;
@@ -160,6 +164,11 @@
   @apply opacity-60 cursor-not-allowed;
 }
 
+/* In RTL: override dir="auto" which defaults to LTR on empty textarea */
+[dir="rtl"] .prompt-input {
+  direction: rtl;
+}
+
 .prompt-input::placeholder {
   color: var(--text-muted);
 }
@@ -256,7 +265,7 @@
   display: none;
   position: absolute;
   bottom: calc(100% + 6px);
-  left: 0;
+  inset-inline-start: 0;
   padding: 8px;
   background-color: var(--surface-base);
   border: 1px solid var(--border-base);
@@ -335,6 +344,7 @@
   .prompt-input {
     min-height: 0;
     padding: 0.5rem 0.75rem;
+    padding-inline-start: 2.5rem; /* preserve space for nav buttons */
     padding-bottom: 0.75rem;
   }