Add PR merge conflict detection (#16)

* Add PR conflict detection using GitHub API mergeable field

- Fetch mergeable field from GitHub API in GitService
- Add has_conflicts getter to PRStatus model
- Display warning emoji (⚠️) for PRs with conflicts
- Prioritize conflicts in highlighting system

* Fix PR conflict detection to use string values from GitHub API

- Changed mergeable type from boolean to string (MERGEABLE/CONFLICTING/UNKNOWN)
- Updated has_conflicts getter to check for 'CONFLICTING' string value
- Fixed is_ready_to_merge to require mergeable === 'MERGEABLE'
- Added comments documenting the possible enum values

* Rework PR conflict detection using local git operations

- Added async checkMergeConflictsAsync() method to GitService
- Uses local git test merge to detect conflicts (no GitHub API needed)
- Added has_merge_conflicts field to GitStatus model
- Created async getGitStatusAsync() method with parallel operations
- Display conflicts in CHANGES column with warning emoji (⚠️)
- Added async git status refresh every 5 seconds
- Conflicts given high priority (Priority 2) in highlighting
- Removed mergeable field from PRStatus (was using GitHub API)

Benefits:
- Works without network/GitHub API access
- Faster local detection
- Shows conflicts even for branches without PRs
- Non-blocking async updates
- Conflicts shown in actionable CHANGES column

* Revert to GitHub API-based conflict detection

- Restored mergeable field to PRStatus model (MERGEABLE/CONFLICTING/UNKNOWN)
- Added back mergeable field fetching in GitService PR methods
- Display conflicts in PR column with ⚠️ emoji (not CHANGES column)
- Restored PR-based highlighting priorities for conflicts
- Removed async git status methods and local conflict detection
- Removed unused useGitStatusAsync hook
- Conflicts now shown in PR column as originally implemented

This reverts back to using GitHub's built-in mergeable API field
for conflict detection instead of local git operations.

Author: promptium-ai

src/components/views/MainView.ts

@@ -91,7 +91,7 @@ export default function MainView(props: Props) {
       const pr = w.pr;
       let prStr = '';
       if (pr?.number) {
-        const badge = (pr.is_merged || pr.state === 'MERGED') ? '⟫' : pr.checks === 'passing' ? '✓' : pr?.checks === 'failing' ? '✗' : pr?.checks === 'pending' ? '⏳' : '';
+        const badge = pr.has_conflicts ? '⚠️' : (pr.is_merged || pr.state === 'MERGED') ? '⟫' : pr.checks === 'passing' ? '✓' : pr?.checks === 'failing' ? '✗' : pr?.checks === 'pending' ? '⏳' : '';
         prStr = `#${pr.number}${badge}`;
       } else if (pr !== undefined) {
         prStr = '-'; // PR data loaded, no PR exists
@@ -185,7 +185,7 @@ export default function MainView(props: Props) {
       const pr = w.pr;
       let prStr = '';
       if (pr?.number) {
-        const badge = (pr.is_merged || pr.state === 'MERGED') ? '⟫' : pr.checks === 'passing' ? '✓' : pr?.checks === 'failing' ? '✗' : pr?.checks === 'pending' ? '⏳' : '';
+        const badge = pr.has_conflicts ? '⚠️' : (pr.is_merged || pr.state === 'MERGED') ? '⟫' : pr.checks === 'passing' ? '✓' : pr?.checks === 'failing' ? '✗' : pr?.checks === 'pending' ? '⏳' : '';
         prStr = `#${pr.number}${badge}`;
       } else if (pr !== undefined) {
         prStr = '-'; // PR data loaded, no PR exists
@@ -249,31 +249,37 @@ export default function MainView(props: Props) {
       }
       // PRIORITY 4+: PR-related priorities (only if PR status has been loaded)
       else if (pr !== undefined) {
-        // PRIORITY 4: PR needs attention (failing checks, conflicts, etc.)
-        if (pr.needs_attention) {
+        // PRIORITY 4: PR has merge conflicts (highest PR priority)
+        if (pr.has_conflicts) {
+          highlightIndex = COLUMNS.PR;
+          highlightColor = COLORS.RED;
+          // pr-conflicts';
+        }
+        // PRIORITY 5: PR needs attention (failing checks, etc.)
+        else if (pr.checks === 'failing') {
           highlightIndex = COLUMNS.PR;
           highlightColor = COLORS.RED;
           // pr-needs-attention';
         }
-        // PRIORITY 5: PR ready to merge (positive action available)
+        // PRIORITY 6: PR ready to merge (positive action available)
         else if (pr.is_ready_to_merge) {
           highlightIndex = COLUMNS.PR;
           highlightColor = COLORS.GREEN;
           // pr-ready-to-merge';
         }
-        // PRIORITY 6: PR exists but no urgent action (informational)
+        // PRIORITY 7: PR exists but no urgent action (informational)
         else if (pr.is_open && pr.number) {
           highlightIndex = COLUMNS.PR;
           highlightColor = COLORS.YELLOW;
           // pr-informational';
         }
-        // PRIORITY 6.5: PR successfully merged (completed work)
+        // PRIORITY 7.5: PR successfully merged (completed work)
         else if (pr.is_merged && pr.number) {
           highlightIndex = COLUMNS.PR;
           highlightColor = COLORS.GREEN;
           // pr-merged';
         }
-        // PRIORITY 7: Claude idle - ready for work (when nothing else needs attention)
+        // PRIORITY 8: Claude idle - ready for work (when nothing else needs attention)
         else if (w.session?.attached && (cs.includes('idle') || cs.includes('active'))) {
           highlightIndex = COLUMNS.AI;
           highlightColor = COLORS.GREEN;

src/models.ts

@@ -34,19 +34,22 @@ export class PRStatus {
   url?: string | null;
   head?: string | null;
   title?: string | null;
+  mergeable?: string | null; // MERGEABLE, CONFLICTING, UNKNOWN
   constructor(init: Partial<PRStatus> = {}) {
     this.number = null;
     this.state = null;
     this.checks = null;
     this.loading = false;
     this.url = null;
     this.title = null;
+    this.mergeable = null;
     Object.assign(this, init);
   }
   get is_merged(): boolean { return this.state === 'MERGED'; }
   get is_open(): boolean { return this.state === 'OPEN'; }
-  get needs_attention(): boolean { return this.checks === 'failing'; }
-  get is_ready_to_merge(): boolean { return this.state === 'OPEN' && this.checks === 'passing' && !this.loading; }
+  get has_conflicts(): boolean { return this.mergeable === 'CONFLICTING'; }
+  get needs_attention(): boolean { return this.checks === 'failing' || this.has_conflicts; }
+  get is_ready_to_merge(): boolean { return this.state === 'OPEN' && this.checks === 'passing' && this.mergeable === 'MERGEABLE' && !this.loading; }
 }
 
 export class SessionInfo {

src/services/GitService.ts

@@ -120,6 +120,7 @@ export class GitService {
     return status;
   }
 
+
   createWorktree(project: string, featureName: string, branchName?: string): boolean {
     const mainRepo = path.join(this.basePath, project);
     const branchesDir = path.join(this.basePath, `${project}${DIR_BRANCHES_SUFFIX}`);
@@ -224,7 +225,7 @@ export class GitService {
   // PR Status Methods
   batchFetchPRData(repoPath: string, opts: {includeChecks?: boolean; includeTitle?: boolean} = {}): Record<string, PRStatus> {
     const prByBranch: Record<string, PRStatus> = {};
-    const fields = ['number', 'state', 'headRefName'];
+    const fields = ['number', 'state', 'headRefName', 'mergeable'];
     const includeChecks = opts.includeChecks !== false;
     const includeTitle = opts.includeTitle !== false;
 
@@ -249,6 +250,7 @@ export class GitService {
         }
         if (pr.url) (status as any).url = pr.url;
         if (includeTitle && pr.title) (status as any).title = pr.title;
+        (status as any).mergeable = pr.mergeable ?? null;
 
         prByBranch[branch] = status;
       }
@@ -259,7 +261,7 @@ export class GitService {
 
   async batchFetchPRDataAsync(repoPath: string, opts: {includeChecks?: boolean; includeTitle?: boolean} = {}): Promise<Record<string, PRStatus>> {
     const prByBranch: Record<string, PRStatus> = {};
-    const fields = ['number', 'state', 'headRefName'];
+    const fields = ['number', 'state', 'headRefName', 'mergeable'];
     const includeChecks = opts.includeChecks !== false;
     const includeTitle = opts.includeTitle !== false;
 
@@ -284,6 +286,7 @@ export class GitService {
         }
         if (pr.url) (status as any).url = pr.url;
         if (includeTitle && pr.title) (status as any).title = pr.title;
+        (status as any).mergeable = pr.mergeable ?? null;
 
         prByBranch[branch] = status;
       }
@@ -395,6 +398,7 @@ export class GitService {
     }
   }
 
+
   private parseBranchCandidates(output: string, existing: string[], base: string): Array<[string, string]> {
     const candidates: Array<[string, string]> = [];
     const seen = new Set<string>();