fix(codebuff): shallow watching and CWD filter for Freebuff

1. Shallow watching: Changed codebuffWatchRoots to enumerate project
   directories and emit shallow watches on <root>/*/chats/ instead of
   recursive watches on <root>/. Reduces inotify usage from O(N*M) to
   O(N) where N=projects and M=sessions.

2. CWD filter: Made skippedSourceAllowsCwdFilter query both
   AgentCodebuff and AgentFreebuff so CWD filtering works for sources
   containing only Freebuff sessions.

Author: scross01

internal/parser/codebuff_provider.go

@@ -63,22 +63,43 @@ func (s codebuffSourceSet) Parse(
 	return outcome, err
 }
 
-// codebuffWatchRoots creates watch plans for recursive watching of
-// each root. Since sessions are two levels deep under chats/, we need
-// recursive watching.
+// codebuffWatchRoots creates shallow watch plans at the chats/ directory
+// level for each project under each root. The on-disk layout is
+// <root>/<project>/chats/<timestamp>/. Watching each <root>/*/chats/
+// directory with Recursive: false creates one watch per project instead
+// of one per session, reducing inotify usage from O(N*M) to O(N).
 func codebuffWatchRoots(roots []string) []WatchRoot {
-	out := make([]WatchRoot, 0, len(roots))
+	var out []WatchRoot
 	for _, root := range roots {
-		out = append(out, WatchRoot{
-			Path:         root,
-			Recursive:    true,
-			IncludeGlobs: []string{"chat-messages.json", "run-state.json", "chat-meta.json"},
-			DebounceKey:  "codebuff:sessions:" + root,
-		})
+		projects, err := os.ReadDir(root)
+		if err != nil {
+			continue
+		}
+		for _, project := range projects {
+			if !project.IsDir() {
+				continue
+			}
+			chatsDir := filepath.Join(root, project.Name(), "chats")
+			if !IsDir(chatsDir) {
+				continue
+			}
+			out = append(out, WatchRoot{
+				Path:         chatsDir,
+				Recursive:    false,
+				IncludeGlobs: []string{"chat-messages.json", "run-state.json", "chat-meta.json"},
+				DebounceKey:  "codebuff:sessions:" + chatsDir,
+			})
+		}
 	}
 	return out
 }
 
+// IsDir reports whether path names an existing directory.
+func IsDir(path string) bool {
+	info, err := os.Stat(path)
+	return err == nil && info.IsDir()
+}
+
 // codebuffClassifyPath maps a changed path back to its source
 // chat-messages.json. Paths are shaped like:
 // <root>/<project>/chats/<timestamp>/chat-messages.json

internal/sync/engine.go

@@ -6545,17 +6545,25 @@ func (e *Engine) skippedSourceAllowsCwdFilter(
 		return true, nil
 	}
 	path := e.effectiveSourcePath(job.path)
-	ids, err := e.db.ListSessionIDsByFilePath(path, string(job.agent))
-	if err != nil {
-		return false, err
-	}
-	for _, id := range ids {
-		session, err := e.db.GetSession(ctx, id)
+	// Freebuff shares the Codebuff provider. Query both agent types
+	// so CWD filtering works for sources containing only Freebuff sessions.
+	agentsToQuery := []string{string(job.agent)}
+	if job.agent == parser.AgentCodebuff {
+		agentsToQuery = append(agentsToQuery, string(parser.AgentFreebuff))
+	}
+	for _, agentStr := range agentsToQuery {
+		ids, err := e.db.ListSessionIDsByFilePath(path, agentStr)
 		if err != nil {
 			return false, err
 		}
-		if session != nil && !e.cwdFilter.allows(session.Cwd) {
-			return false, nil
+		for _, id := range ids {
+			session, err := e.db.GetSession(ctx, id)
+			if err != nil {
+				return false, err
+			}
+			if session != nil && !e.cwdFilter.allows(session.Cwd) {
+				return false, nil
+			}
 		}
 	}
 	return true, nil