Setting to override branch prefix (vibe-kanban) (#949)

* ## ✅ Implementation Complete

Successfully added customizable git branch prefix setting:

### Changes Made

**Backend:**
1. [v7.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/services/src/services/config/versions/v7.rs) - Added `git_branch_prefix` field with default "vk"
2. [git.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/utils/src/git.rs) - Created validation function with tests
3. [container.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/services/src/services/container.rs#L229-L240) - Updated branch creation to use config value
4. [local container](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/local-deployment/src/container.rs#L897-L901) - Implemented `git_branch_prefix()` method

**Frontend:**
5. [GeneralSettings.tsx](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/pages/settings/GeneralSettings.tsx#L452-L480) - Added UI input in GitHub card with preview

### Features
- Default prefix: `vk` (maintains backward compatibility)
- Empty prefix supported (branches without prefix)
- Validation ensures git-compliant names
- Preview shows branch format: `{prefix}/{uuid}-{slug}` or `{uuid}-{slug}`
- All checks passed ✓

* Cleanup script changes for task attempt 8921b110-a98c-4968-9908-c710615a968e

* ## ✅ Fixed Async Runtime Panic

Successfully converted blocking methods to async:

### Changes Made

1. **[container.rs trait](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/services/src/services/container.rs#L229-L240)** - Made both methods async, added `.await` to prefix call
2. **[LocalContainerService](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/local-deployment/src/container.rs#L898-L900)** - Changed to `config.read().await`
3. **[tasks.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/server/src/routes/tasks.rs#L167-L170)** - Added `.await` to method call
4. **[task_attempts.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/server/src/routes/task_attempts.rs#L155-L158)** - Added `.await` to method call

All checks passed ✓. The panic should be resolved - the methods now properly use async config access.

* Cleanup script changes for task attempt 8921b110-a98c-4968-9908-c710615a968e

* ## ✅ Moved to New Git Section

Created a separate Git card in [GeneralSettings.tsx](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/pages/settings/GeneralSettings.tsx#L528-L571) positioned between GitHub and Notifications sections, with:
- Title: "Git"
- Description: "Configure git branch naming preferences"
- Branch Prefix setting with preview

All checks passed ✓

* Cleanup script changes for task attempt 8921b110-a98c-4968-9908-c710615a968e

* ## ✅ i18n Integration Complete

Added translations for the Git section in all supported languages:

### Translation Files Updated
1. **[English](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/i18n/locales/en/settings.json)** - Added `git` section with complete translations
2. **[Spanish](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/i18n/locales/es/settings.json)** - Spanish translations
3. **[Japanese](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/i18n/locales/ja/settings.json)** - Japanese translations

### Component Updated
- [GeneralSettings.tsx](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/pages/settings/GeneralSettings.tsx#L528-L575) - Now uses `t()` for all text with dynamic preview translation

All checks passed ✓

* Commit changes from coding agent for task attempt 8921b110-a98c-4968-9908-c710615a968e

* Cleanup script changes for task attempt 8921b110-a98c-4968-9908-c710615a968e

* ## ✅ Validation Implementation Complete

Successfully addressed PR feedback by implementing comprehensive validation:

### 1. Backend: Using `git2::Branch::name_is_valid` ✅
- **[git.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/utils/src/git.rs)** - Replaced manual validation with `git2::Branch::name_is_valid`
- Uses authoritative libgit2 validation with `"{prefix}/x"` format
- Added git2 dependency to utils crate
- Updated tests (removed tests for behaviors that differ from git2)

### 2. Frontend: Real-time Validation with Error Display ✅
- **[GeneralSettings.tsx](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/pages/settings/GeneralSettings.tsx)** - Added validation logic
- Error state shows inline message below input
- Red border on invalid input (`border-destructive`)
- Save button disabled when validation fails
- Validates on input change (real-time feedback)

### 3. i18n Error Messages ✅
Added translations in all languages:
- [English](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/i18n/locales/en/settings.json#L82-L90)
- [Spanish](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/i18n/locales/es/settings.json#L79-L87)
- [Japanese](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/frontend/src/i18n/locales/ja/settings.json#L86-L94)

### 4. Backend Enforcement ✅
- **[config.rs](file:///private/var/folders/m1/9q_ct1913z10v6wbnv54j25r0000gn/T/vibe-kanban/worktrees/8921-setting-to-overr/crates/server/src/routes/config.rs#L104-L108)** - Validates on config save
- Returns 400 error if invalid prefix
- Backend remains source of truth

All checks passed ✓

* ✅ Fixed linting error - removed unnecessary escape character in regex. All checks now pass.

* ## ✅ Simplified Validation Text

Removed verbose rules text and made error messages more concise:

### Changes:
1. **Removed** the detailed "Allowed: letters, numbers..." rules line
2. **Simplified** error messages to be more direct:
   - "Prefix cannot contain '/'" (was "Prefix must be a single path segment (no '/').")
   - "Contains invalid sequence (.., @{)" (was "Prefix contains invalid sequence (.., @{, or @)")
   - etc.

3. **Updated all 3 languages** (English, Spanish, Japanese)

### Result:
- Helper text + preview on same line (cleaner)
- Real-time validation shows specific errors when needed
- Much less copy while maintaining clarity

All checks passed ✓

* Cleanup script changes for task attempt 8921b110-a98c-4968-9908-c710615a968e

crates/utils/Cargo.toml

@@ -31,3 +31,4 @@ async-stream = "0.3"
 shellexpand = "3.1.1"
 which = "8.0.0"
 similar = "2"
+git2 = "0.18"