Add 'b' key for branch-based session creation

[jellydn]

Add 'b' Key for Branch-Based Session Creation with Remote Sync

Addresses #88 (provides manual workaround for flexible branch naming)

What

This PR adds comprehensive branch-based session creation functionality via the 'b' key, implementing a three-step workflow that allows users to create sessions with custom git branches, now enhanced with remote branch sync detection and session name preservation.

Key Features Added:

• 'b' key functionality: Create sessions with custom branch names
• Three-step workflow: Session name → Branch name → Source branch
• 🆕 Remote sync detection: Automatically check if source/target branches need sync with origin
• 🆕 Session name preservation: Maintains user session names instead of overwriting with branch names
• Smart defaults: Automatic detection of main/develop branches
• Text input modals: Consistent UI across all input steps
• Branch validation: Git-compliant branch name validation
• No prefix interference: User-specified branch names used exactly as provided

Why

Problem Statement:

Users needed a way to create sessions with specific git branch names for feature development, but the existing 'n' key only supported auto-generated branch names with configured prefixes.

Issues Addressed:

1. Missing Branch Control: No way to specify custom branch names like feat/user-auth or hotfix/critical-bug
2. 🆕 Outdated Source Branches: Creating branches from stale local source branches that diverged from remote
3. 🆕 Session Name Override: User session names being replaced with branch names
4. Modal Display Problems: Text appeared vertically instead of horizontally in input fields
5. Title Setting Errors: "Cannot change title of started instance" errors in branch workflow
6. Branch Prefix Interference: User-specified branches were getting unwanted prefixes
7. Linting Issues: Non-idiomatic if-else chains and unchecked errors
8. Import Problems: Missing aliases causing build failures

How

Implementation Details:

1. Core Branch Workflow (app/app.go) - Enhanced

// Enhanced workflow with remote sync checks
case stateSourceBranch:
    // 🆕 Check source branch sync first
    sourceExists, sourceNeedsSync, err := session.CheckRemoteBranchStatic(".", sourceBranch)
    if sourceExists && sourceNeedsSync {
        // Show sync confirmation for source branch
        message := "Source branch 'main' is out of sync with remote. Sync before creating? (y/n)"
    }
    
    // 🆕 Then check target branch sync  
    exists, needsSync, err := session.CheckRemoteBranchStatic(".", targetBranch)
    if exists && needsSync {
        // Show sync confirmation for target branch
        message := "Target branch 'feature' has different commits. Sync before creating? (y/n)"
    }

2. 🆕 Remote Branch Sync System (session/git/worktree_ops.go)

// Static methods that work before instance initialization
func CheckRemoteBranchStatic(repoPath, branchName string) (exists bool, needsSync bool, err error)
func SyncWithRemoteBranchStatic(repoPath, branchName string) error

// Two-stage sync confirmation workflow
func (m *home) syncSourceThenCheckTarget(selected *session.Instance, sourceBranch string)
func (m *home) checkTargetBranchAndProceed(selected *session.Instance, sourceBranch string) 

3. 🆕 Session Name Preservation (app/app.go)

Before: Always overwrote session title with branch name

// WRONG: Always overwrote user's session name
if err := selected.SetTitle(m.pendingBranchName); err != nil {

After: Preserves user session names

// CORRECT: Only set branch name as title if no title exists
if selected.Title == "" {
    if err := selected.SetTitle(m.pendingBranchName); err != nil {

4. Instance Lifecycle Fix

Before: Instance started immediately after naming, preventing title updates

// BROKEN: Started too early
case tea.KeyEnter:
    instance.Start(true) // ❌ Makes title immutable

After: Instance starts only after complete configuration

// FIXED: Start timing based on workflow needs
if !m.branchAfterName && !m.promptAfterName {
    instance.Start(true) // ✅ Start when ready
}

5. UI Component Improvement (ui/overlay/textInput.go)

Before: Used textarea.Model (multi-line) causing vertical text display

textarea      textarea.Model  // ❌ Wrong component

After: Switched to textinput.Model (single-line) for proper display

textInput     textinput.Model  // ✅ Correct component

🆕 Enhanced User Experience Flow:

Before:

1. Press 'b' → Enter session name → Enter branch → Session renamed to branch name
2. No remote sync checking → potential outdated branches

After:

1. Press 'b' → Enter session name "my-feature" → Enter branch name "feat/auth"
2. Check source branch sync → "Source branch 'main' is out of sync. Sync? (y/n)"
3. Check target branch sync → "Target branch 'feat/auth' has different commits. Sync? (y/n)"  
4. Create session named "my-feature" with up-to-date branch "feat/auth"

Testing & Validation:

• ✅ All existing tests pass (no regressions)
• ✅ 🆕 Comprehensive test coverage for sync functionality (app/branch_sync_test.go)
• ✅ 🆕 Session name preservation tests (TestSessionTitlePreservation)
• ✅ 🆕 Remote branch sync tests (TestSourceBranchSyncCheck)
• ✅ Build succeeds with zero linting issues
• ✅ Both 'n' and 'b' key workflows working correctly

Workflow Comparison:

Feature	'n' Key (Auto)	'b' Key (Custom)
Session Name	✅ User types	✅ User types (🆕 preserved)
Branch Name	❌ Auto-generated	✅ User specifies
Source Branch	❌ Default only	✅ User selects
🆕 Source Sync Check	❌ No	✅ Yes
🆕 Target Sync Check	❌ No	✅ Yes
Branch Prefix	✅ Applied	❌ Not applied
Use Case	Quick sessions	Feature branches

Examples

🆕 Enhanced 'b' Key Workflow:

1. Press b → Enter session name: auth-feature-work
2. Enter branch name: feat/user-authentication
3. Enter source branch: develop
4. 🆕 Source sync check: "Source branch 'develop' is out of sync with remote. Sync before creating? (y/n)"
5. 🆕 Target sync check: "Target branch 'feat/user-authentication' has different commits. Sync before creating? (y/n)"
6. Result: Session named auth-feature-work with synced branch feat/user-authentication from updated develop

Addresses Issue #88 - Flexible Branch Naming:

While this PR doesn't implement template-based automatic branch naming, it provides a manual solution that supports all the patterns requested in #88:

• ✅ fix/issue-123-auth-bug - User can type exactly this
• ✅ feature/456/user-dashboard - User can type exactly this
• ✅ {user}/issue-789 - User can manually enter their username
• ✅ Any custom pattern - Complete flexibility through manual input

This gives users immediate access to flexible branch naming while a future PR could add template automation.

Backwards Compatibility:

• 'n' key: Works exactly as before with prefix
• 'p' key: Unchanged functionality
• All existing configurations and workflows preserved

🆕 Files Changed (Latest):

Core Enhancements:

• app/app.go - Enhanced workflow with remote sync detection and session name preservation
• app/branch_sync_test.go - NEW: Comprehensive tests for sync functionality
• session/git/worktree_ops.go - Added static remote branch checking methods
• session/git/util_test.go - NEW: Tests for remote branch operations
• session/instance.go - Added wrapper functions for static git operations

Previous Changes:

• keys/keys.go - Key binding for 'b'
• ui/overlay/textInput.go - UI component fix
• config/config_test.go - Error handling fixes
• session/tmux/tmux.go - Error handling fixes
• Multiple files - Import and linting fixes

This comprehensive implementation provides users with full control over branch-based development workflows with intelligent remote sync management while maintaining all existing functionality.

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[jellydn]

I have read the CLA Document and I hereby sign the CLA

[jellydn]

🚀 Major Updates Since Last Week

Hey team! I've made significant enhancements to the branch creation workflow based on testing and user feedback. Here's what's new in the latest commit:

🔄 Remote Branch Sync Detection & Management

Problem Solved: Users were creating branches from outdated local source branches that had diverged from remote origin, leading to merge conflicts and lost commits.

Solution: Added intelligent 2-stage sync detection:

1. Source Branch Sync Check

• Before creating any branch, check if the source branch (e.g., main, develop) needs sync
• User prompt: "Source branch 'main' is out of sync with remote. Sync before creating new branch? (y/n)"
• Prevents branches from being created off stale local commits

2. Target Branch Sync Check

• Check if target branch name already exists on remote with different commits
• User prompt: "Target branch 'feat/auth' has different commits. Sync before creating? (y/n)"
• Handles cases where remote branch was updated by teammates

💾 Session Name Preservation

Problem Solved: The 'b' key workflow was overwriting user session names with branch names.

Before: User enters session name "my-auth-work" → gets session named "feat/auth-flow" ❌
After: User enters session name "my-auth-work" → keeps session named "my-auth-work" ✅

This maintains clear separation between session organization and git branch naming.

🛠️ Technical Implementation

New Static Methods (session/git/worktree_ops.go):

func CheckRemoteBranchStatic(repoPath, branchName string) (exists bool, needsSync bool, err error)
func SyncWithRemoteBranchStatic(repoPath, branchName string) error

Enhanced State Machine (app/app.go):

• Added syncSourceThenCheckTarget() and checkTargetBranchAndProceed() methods
• Two-stage confirmation workflow using stateSyncConfirm
• Contextual overlay messages for different sync scenarios

Session Title Logic:

// Only overwrite title if none provided (preserves 'b' key user input)
if selected.Title == "" {
    selected.SetTitle(m.pendingBranchName)
}

🧪 Comprehensive Testing

New Test Suite (app/branch_sync_test.go):

• TestSyncConfirmationStateTransitions - State management
• TestSyncConfirmationKeyHandling - User input handling
• TestSessionTitlePreservation - Session name preservation
• TestSourceBranchSyncCheck - Remote sync detection
• TestSyncConfirmationFlow - End-to-end workflows

All tests pass - zero regressions, full backward compatibility maintained.

📈 Impact on User Experience

Before:

Press 'b' → name session → name branch → create (possibly from stale source)
Result: Session named after branch, potential git conflicts

After:

Press 'b' → name session → name branch → sync source? → sync target? → create
Result: Custom session name preserved, branches always up-to-date

🔧 Why These Changes Matter

1. Prevents Git Conflicts: No more surprises from outdated source branches
2. Better Organization: Session names reflect user intent, not technical details
3. Safer Workflows: Users make informed decisions about remote sync
4. Team Collaboration: Handles scenarios where teammates updated remote branches

This brings the branch creation workflow up to production-ready standards for team development!

Ready for review - all functionality tested and working seamlessly with existing workflows.

[matthew-petty]

I submitted a PR #211 with a substantially similar goal. I chose a simpler approach with no upstream checking and no option to use an arbitrary branch. I did not intend to duplicate functionality across to PRs. #211 is a solution I implemented for my personal workflows.