feat(claudewatcher): exclude whole project directories from ingestion

CLAUDE_INGEST_SKIP_PROJECTS takes filepath.Match globs tested against
the project directory NAME, and a matching directory is skipped during
the directory WALK — so its files are never opened and their content
never enters the process. That is a stronger property than filtering
after reading, and the difference is observable: without SkipDir,
WalkDir lists the directory's entries, and an unreadable one aborts the
entire walk, silently stopping ingestion for every other project.

Globs rather than exact names because a project directory is derived
from the session's working directory, so a git worktree yields an
ephemeral name no exact-match list could keep up with.

An unparseable pattern refuses to run. filepath.Match returns an error
ALONGSIDE a false match, so a bad pattern checked per-file would ingest
the directory while the log complained — the failure nobody notices.
Validated once, up front, in both entry points.

This complements the client-name scrubber rather than replacing it. The
scrubber drops individual turns whose content matches a client
identity; this excludes whole workspaces whose content is confidential
in ways no pattern reliably recognises. Learnings from excluded
sessions are captured deliberately through the session-close ritual
instead.

Recorded caveat: the project directory reflects the session's working
directory, NOT the repositories it touches. A session run from ~/dev
that reads an excluded repo is not excluded by this. The scrubber
remains the control for content; this is a control for workspaces.

A mutation test earned the strongest assertion here: the original tests
could not distinguish SkipDir from filtering after the walk, because
neither opens files. The unreadable-directory test can.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ingestion/internal/claudewatcher/watcher.go

@@ -45,6 +45,25 @@ type Config struct {
 	Sink        Sink
 	Cursors     *CursorStore
 	Logger      *slog.Logger
+
+	// SkipProjects excludes whole project directories from ingestion, as
+	// filepath.Match globs tested against the project directory NAME (the
+	// basename, e.g. "-home-mathias-dev"), not the full path.
+	//
+	// Globs rather than exact names because a project directory is derived
+	// from the session's working directory, so a git worktree yields an
+	// ephemeral name like
+	// "-home-mathias-dev--claude-worktrees-bridge-cse-017xoC..." that no
+	// exact-match list could keep up with.
+	//
+	// Matching directories are skipped during the directory WALK, so their
+	// files are never opened and their content never enters this process —
+	// which is a stronger property than filtering it out afterwards.
+	//
+	// An unparseable pattern stops the watcher. A silently dropped skip rule
+	// means ingesting what was meant to be excluded, and that is not
+	// noticeable after the fact.
+	SkipProjects []string
 }
 
 // Watch runs the polling loop until ctx is cancelled. Returns ctx.Err()
@@ -68,6 +87,9 @@ func Watch(ctx context.Context, cfg Config) error {
 	if cfg.Logger == nil {
 		cfg.Logger = slog.Default()
 	}
+	if err := validateSkipPatterns(cfg.SkipProjects); err != nil {
+		return err
+	}
 	cfg.Logger.Info("claudewatcher: started",
 		"sessions_dir", cfg.SessionsDir,
 		"host", cfg.Host,
@@ -91,7 +113,7 @@ func Watch(ctx context.Context, cfg Config) error {
 // runTick is one polling pass. Exposed (lowercase) for tests via
 // TickOnce.
 func runTick(ctx context.Context, cfg Config) {
-	files, err := listSessionFiles(cfg.SessionsDir)
+	files, err := listSessionFiles(cfg.SessionsDir, cfg.SkipProjects, cfg.Logger)
 	if err != nil {
 		cfg.Logger.Warn("claudewatcher: list session files", "err", err)
 		return
@@ -119,17 +141,52 @@ func TickOnce(ctx context.Context, cfg Config) error {
 	if cfg.Logger == nil {
 		cfg.Logger = slog.Default()
 	}
+	if err := validateSkipPatterns(cfg.SkipProjects); err != nil {
+		return err
+	}
 	runTick(ctx, cfg)
 	return nil
 }
 
-func listSessionFiles(root string) ([]string, error) {
+// validateSkipPatterns rejects a pattern filepath.Match cannot parse.
+//
+// Checked up front rather than per file: a bad pattern that only failed at
+// match time would be reported once per session file per tick, and — worse —
+// filepath.Match returns an error alongside a false match, so the directory
+// would be ingested while the log complained.
+func validateSkipPatterns(patterns []string) error {
+	for _, p := range patterns {
+		if _, err := filepath.Match(p, "probe"); err != nil {
+			return fmt.Errorf("invalid skip-project pattern %q: %w", p, err)
+		}
+	}
+	return nil
+}
+
+// skipProject reports whether a project directory name matches any pattern.
+func skipProject(name string, patterns []string) bool {
+	for _, p := range patterns {
+		// The error case is already excluded by validateSkipPatterns.
+		if ok, _ := filepath.Match(p, name); ok {
+			return true
+		}
+	}
+	return false
+}
+
+func listSessionFiles(root string, skip []string, log *slog.Logger) ([]string, error) {
 	var out []string
 	err := filepath.WalkDir(root, func(path string, d os.DirEntry, walkErr error) error {
 		if walkErr != nil {
 			return walkErr
 		}
 		if d.IsDir() {
+			// SkipDir, so nothing inside is even listed. The files are never
+			// opened and their content never reaches this process.
+			if path != root && skipProject(d.Name(), skip) {
+				log.Info("claudewatcher: project skipped by configuration", "project", d.Name())
+				return filepath.SkipDir
+			}
 			return nil
 		}
 		if !strings.HasSuffix(path, ".jsonl") {