merge: integrate oss branch — budget gating, MCP back-channel, events, loopback-only bind

Key features from OSS branch:
- Budget gating: rolling per-provider spend caps with BUDGET_EXCEEDED task state
- Agent MCP back-channel: runners mint tokens; /mcp endpoint resolves them
- Chatbot MCP server at /chatbot/mcp (requires api_token in config)
- Event timeline: unified event stream replacing ad-hoc question/summary flows
- Loopback-only default bind (127.0.0.1:8484); external_bind_allowed=true to expose
- repository_url required on task creation (enforces traceability)
- Auto-checker: spawns verification task after each execution

Conflict resolutions:
- serve.go: keep cfg.Runners.XEnabled() conditional registration from main + agentRegistry from oss
- config.go: keep RunnersConfig from main + BudgetConfig/ExternalBindAllowed from oss
- server.go: handleStaticFiles (base-path rewrite) kept; deduplicated duplicate from both sides
- executor/claude.go: accepted oss deletion (ClaudeRunner replaced by ContainerRunner)
- container_test.go: added noopChannel + AgentChannel parameter to Run call

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/internal/api/agentmcp_endpoint_test.go b/internal/api/agentmcp_endpoint_test.go
new file mode 100644
index 0000000..b2f77d3
--- /dev/null
+++ b/internal/api/agentmcp_endpoint_test.go
@@ -0,0 +1,104 @@
+package api
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/thepeterstone/claudomator/internal/executor"
+	"github.com/thepeterstone/claudomator/internal/storage"
+)
+
+type fakeAgentChannel struct{ progress []string }
+
+func (f *fakeAgentChannel) AskUser(context.Context, string) (string, error) {
+	return "", executor.ErrAgentBlocked
+}
+func (f *fakeAgentChannel) ReportSummary(context.Context, string) error { return nil }
+func (f *fakeAgentChannel) SpawnSubtask(context.Context, executor.SubtaskSpec) (string, error) {
+	return "sub", nil
+}
+func (f *fakeAgentChannel) RecordProgress(_ context.Context, m string) error {
+	f.progress = append(f.progress, m)
+	return nil
+}
+
+type tokenRT struct {
+	token string
+	base  http.RoundTripper
+}
+
+func (b tokenRT) RoundTrip(r *http.Request) (*http.Response, error) {
+	r = r.Clone(r.Context())
+	r.Header.Set("Authorization", "Bearer "+b.token)
+	return b.base.RoundTrip(r)
+}
+
+func TestServer_MountsAgentMCPEndpoint(t *testing.T) {
+	store, err := storage.Open(filepath.Join(t.TempDir(), "test.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer store.Close()
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	pool := executor.NewPool(1, map[string]executor.Runner{}, store, logger)
+
+	reg := executor.NewRegistry()
+	fc := &fakeAgentChannel{}
+	token, _ := reg.Mint(fc)
+
+	srv := NewServer(store, pool, reg, logger, "claude", "gemini")
+	ts := httptest.NewServer(srv.Handler())
+	defer ts.Close()
+
+	client := mcp.NewClient(&mcp.Implementation{Name: "test", Version: "1"}, nil)
+	cs, err := client.Connect(context.Background(), &mcp.StreamableClientTransport{
+		Endpoint:   ts.URL + "/mcp",
+		HTTPClient: &http.Client{Transport: tokenRT{token: token, base: http.DefaultTransport}},
+	}, nil)
+	if err != nil {
+		t.Fatalf("connect to mounted /mcp: %v", err)
+	}
+	defer cs.Close()
+
+	if _, err := cs.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      "record_progress",
+		Arguments: map[string]any{"message": "via api server"},
+	}); err != nil {
+		t.Fatalf("CallTool through api server: %v", err)
+	}
+	if len(fc.progress) != 1 || fc.progress[0] != "via api server" {
+		t.Errorf("tool call did not reach channel: %+v", fc.progress)
+	}
+}
+
+func TestServer_NoRegistry_NoMCPRoute(t *testing.T) {
+	store, err := storage.Open(filepath.Join(t.TempDir(), "test.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer store.Close()
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))
+	pool := executor.NewPool(1, map[string]executor.Runner{}, store, logger)
+
+	// nil registry → /mcp must not be mounted.
+	srv := NewServer(store, pool, nil, logger, "claude", "gemini")
+	ts := httptest.NewServer(srv.Handler())
+	defer ts.Close()
+
+	resp, err := http.Post(ts.URL+"/mcp", "application/json", http.NoBody)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	// Unmounted: the catch-all "GET /" route rejects POST with 405. A mounted
+	// MCP handler would instead respond (e.g. 400 for the missing token).
+	if resp.StatusCode == http.StatusBadRequest {
+		t.Errorf("expected /mcp to be absent without a registry, got 400 (handler ran)")
+	}
+}