feat(mcp): brain_pending + brain_promote tools + REST routes (#38)

Wires the curation primitives into the MCP surface (all three sites:
tools() descriptors, handleCall dispatch, package doc) and registers the
GET /pending + POST /promote REST routes. brain_promote additionally
re-indexes the promoted note into the graph (best-effort), matching the
other write paths. brain_pending is the human-review-queue complement to
the agent-facing brain_write.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ingestion/internal/mcp/handlers_test.go

@@ -332,3 +332,61 @@ func TestSessionLogRequiresSessionID(t *testing.T) {
 	resp := toolCall(t, srv, "session_log", map[string]any{"skill": "tdd"})
 	require.NotNil(t, resp["error"])
 }
+
+func TestBrainPendingListsRaw(t *testing.T) {
+	brainDir := t.TempDir()
+	raw := filepath.Join(brainDir, "raw")
+	require.NoError(t, os.MkdirAll(raw, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(raw, "2026-06-01-x.md"),
+		[]byte("---\ncreated_at: 2026-06-01T00:00:00Z\n---\npending body\n"), 0o644))
+	srv := mcp.NewServer(brainDir, nil, nil, nil)
+
+	resp := toolCall(t, srv, "brain_pending", map[string]any{})
+	require.Nil(t, resp["error"])
+	text := resp["result"].(map[string]any)["content"].([]any)[0].(map[string]any)["text"].(string)
+	assert.Contains(t, text, "2026-06-01-x.md")
+	assert.Contains(t, text, "pending body")
+}
+
+func TestBrainPendingEmpty(t *testing.T) {
+	srv := mcp.NewServer(t.TempDir(), nil, nil, nil)
+	resp := toolCall(t, srv, "brain_pending", map[string]any{})
+	require.Nil(t, resp["error"])
+	text := resp["result"].(map[string]any)["content"].([]any)[0].(map[string]any)["text"].(string)
+	assert.Contains(t, text, `"pending":[]`)
+}
+
+func TestBrainPromoteMovesToWiki(t *testing.T) {
+	brainDir := t.TempDir()
+	raw := filepath.Join(brainDir, "raw")
+	require.NoError(t, os.MkdirAll(raw, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(raw, "2026-06-01-decision.md"),
+		[]byte("---\ncreated_at: 2026-06-01T00:00:00Z\n---\n# D\n\nbody\n"), 0o644))
+	srv := mcp.NewServer(brainDir, nil, nil, nil)
+
+	resp := toolCall(t, srv, "brain_promote", map[string]any{
+		"filename": "2026-06-01-decision.md", "wing": "jepa-fx", "hall": "decisions",
+	})
+	require.Nil(t, resp["error"], "got: %v", resp["error"])
+	text := resp["result"].(map[string]any)["content"].([]any)[0].(map[string]any)["text"].(string)
+	assert.Contains(t, text, "wiki/jepa-fx/decisions/decision.md")
+
+	_, err := os.Stat(filepath.Join(brainDir, "wiki/jepa-fx/decisions/decision.md"))
+	require.NoError(t, err)
+	_, srcErr := os.Stat(filepath.Join(raw, "2026-06-01-decision.md"))
+	assert.True(t, os.IsNotExist(srcErr), "source removed")
+}
+
+func TestBrainPromoteInvalidHallErrors(t *testing.T) {
+	brainDir := t.TempDir()
+	raw := filepath.Join(brainDir, "raw")
+	require.NoError(t, os.MkdirAll(raw, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(raw, "x.md"), []byte("body\n"), 0o644))
+	srv := mcp.NewServer(brainDir, nil, nil, nil)
+	resp := toolCall(t, srv, "brain_promote", map[string]any{
+		"filename": "x.md", "wing": "a", "hall": "garbage",
+	})
+	require.NotNil(t, resp["error"])
+	_, srcErr := os.Stat(filepath.Join(raw, "x.md"))
+	assert.NoError(t, srcErr, "source untouched on validation error")
+}