fix: statusline crash handling, color validation, git staging rules

Fixed three critical bugs and documented findings:

1. hooks/gsd-statusline.js - Added error handling for file system operations
   - Wrapped fs.readdirSync and fs.statSync in try-catch
   - Prevents crashes from permission errors or race conditions

2. bin/install.js - Added hex color validation
   - Validates hex color format (#RGB or #RRGGBB)
   - Prevents invalid colors from being written to config

3. commands/gsd/execute-phase.md - Fixed git staging violation
   - Replaced 'git add -u' with individual file staging
   - Maintains consistency with documented git commit rules

Documentation:
- BUG_REPORT.md - Comprehensive review findings (8 bugs total)
- FIXES_APPLIED.md - Details of fixes applied and testing recommendations

Known issues remaining:
- JSON config parsing uses fragile grep/sed (requires jq or refactor)
- Documented workarounds and recommendations for future fixes

https://claude.ai/code/session_01RAgU8GfJ2dwtBSmJDGzpWA

Co-authored-by: Claude <noreply@anthropic.com>

hooks/gsd-statusline.js

@@ -48,17 +48,21 @@ process.stdin.on('end', () => {
     const homeDir = os.homedir();
     const todosDir = path.join(homeDir, '.claude', 'todos');
     if (session && fs.existsSync(todosDir)) {
-      const files = fs.readdirSync(todosDir)
-        .filter(f => f.startsWith(session) && f.includes('-agent-') && f.endsWith('.json'))
-        .map(f => ({ name: f, mtime: fs.statSync(path.join(todosDir, f)).mtime }))
-        .sort((a, b) => b.mtime - a.mtime);
+      try {
+        const files = fs.readdirSync(todosDir)
+          .filter(f => f.startsWith(session) && f.includes('-agent-') && f.endsWith('.json'))
+          .map(f => ({ name: f, mtime: fs.statSync(path.join(todosDir, f)).mtime }))
+          .sort((a, b) => b.mtime - a.mtime);
 
-      if (files.length > 0) {
-        try {
-          const todos = JSON.parse(fs.readFileSync(path.join(todosDir, files[0].name), 'utf8'));
-          const inProgress = todos.find(t => t.status === 'in_progress');
-          if (inProgress) task = inProgress.activeForm || '';
-        } catch (e) {}
+        if (files.length > 0) {
+          try {
+            const todos = JSON.parse(fs.readFileSync(path.join(todosDir, files[0].name), 'utf8'));
+            const inProgress = todos.find(t => t.status === 'in_progress');
+            if (inProgress) task = inProgress.activeForm || '';
+          } catch (e) {}
+        }
+      } catch (e) {
+        // Silently fail on file system errors - don't break statusline
       }
     }