fix(claudewatcher): tag session-dump notes source_type: internal

brain-gardener#5: the audit's unsourced check was flagging 59 raw
claudewatcher session dumps as high-severity hallucination risk,
because it can't distinguish a first-party observation (a session
transcript) from an external claim needing citation.

Adds WriteNoteOptions.SourceType, emitted as source_type: <value> in
the wing/hall frontmatter route. claudeSink (the claudewatcher sink)
now always sets source_type: internal on the notes it writes.

ingestion/cmd/server/main_test.go

@@ -0,0 +1,36 @@
+// ingestion/cmd/server/main_test.go
+package main
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/claudewatcher"
+)
+
+func TestClaudeSink_IngestTagsSourceTypeInternal(t *testing.T) {
+	dir := t.TempDir()
+	sink := &claudeSink{brainDir: dir, logger: slog.New(slog.NewTextHandler(os.Stderr, nil))}
+
+	err := sink.Ingest(context.Background(), claudewatcher.Batch{
+		Host:      "koala",
+		FilePath:  "/host-home-claude/projects/-home-mathias-dev/abc.jsonl",
+		SessionID: "abc",
+		ProjectID: "-home-mathias-dev",
+		Turns: []claudewatcher.Turn{
+			{Type: "assistant", Content: "did a thing"},
+		},
+	})
+	require.NoError(t, err)
+
+	got, err := os.ReadFile(filepath.Join(dir, "wiki", "claude-sessions", "facts", "session-koala-abc.md"))
+	require.NoError(t, err)
+	assert.Contains(t, string(got), "source_type: internal")
+	assert.Contains(t, string(got), "wing: claude-sessions")
+}