fix(ingest): route raw claude-session dumps to non-indexed archive, not wiki

claudeSink wrote every raw transcript into brain/wiki/claude-sessions/facts/
(BM25-indexed), duplicating what ai-sessions' curated summaries already
cover and out-ranking them in search (177,818 vs 45,335 BM25 weight on the
same query, per ai-sessions#10 investigation). Raw dumps now land in
brain/archive/claude-sessions/<host>/ — kept for deep lookups, never
indexed, never deleted.

Refs: ai-sessions#10

ingestion/cmd/server/main.go

@@ -36,10 +36,12 @@ import (
 	"github.com/mathiasbq/hyperguild/ingestion/internal/watcher"
 )
 
-// claudeSink converts each claudewatcher.Batch into one wiki note under
-// brain/wiki/claude-sessions/facts/. v1 emits one note per session
-// keyed by host + session id; classifier-driven hall routing is a
-// follow-up (hyperguild#27 v2).
+// claudeSink converts each claudewatcher.Batch into a raw session dump
+// under brain/archive/claude-sessions/<host>/. Deliberately NOT a wiki
+// note (api.WriteNote / brain/wiki/) — raw full transcripts out-ranked
+// curated ai-sessions summaries in BM25 (177,818 vs 45,335 on the same
+// query) and duplicated content already summarized elsewhere. Kept for
+// deep lookups, never indexed. See ai-sessions#10.
 type claudeSink struct {
 	brainDir string
 	logger   *slog.Logger
@@ -67,17 +69,14 @@ func (s *claudeSink) Ingest(ctx context.Context, b claudewatcher.Batch) error {
 		sb.WriteString("\n\n")
 	}
 	slug := "session-" + b.Host + "-" + b.SessionID
-	if _, err := api.WriteNote(s.brainDir, api.WriteNoteOptions{
-		Filename:   slug,
-		Wing:       "claude-sessions",
-		Hall:       "facts",
-		Type:       "source",
-		Domain:     b.ProjectID,
-		Content:    sb.String(),
-		SourceType: "internal", // raw session transcript, not an external claim (brain-gardener#5)
-	}); err != nil {
-		return fmt.Errorf("write claude session note: %w", err)
+	dest := filepath.Join(s.brainDir, "archive", "claude-sessions", b.Host, slug+".md")
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
+		return fmt.Errorf("create claude-sessions archive dir: %w", err)
 	}
+	if err := os.WriteFile(dest, []byte(sb.String()), 0o644); err != nil {
+		return fmt.Errorf("write claude session archive: %w", err)
+	}
+	s.logger.Debug("claude session archived (non-indexed)", "path", dest)
 	return nil
 }