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, 21 insertions, 0 deletions

diff --git a/internal/api/validate_test.go b/internal/api/validate_test.go
index c3d7b1f..60fec14 100644
--- a/internal/api/validate_test.go
+++ b/internal/api/validate_test.go
@@ -3,11 +3,32 @@ package api
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"net/http/httptest"
+	"os"
+	"path/filepath"
 	"testing"
 )
 
+// createFakeClaude writes a stub `claude` script that prints the given output
+// and exits with the given code, returning its path for use as a binary
+// override in tests.
+func createFakeClaude(t *testing.T, output string, exitCode int) string {
+	t.Helper()
+	dir := t.TempDir()
+	outputFile := filepath.Join(dir, "output.json")
+	if err := os.WriteFile(outputFile, []byte(output), 0600); err != nil {
+		t.Fatal(err)
+	}
+	script := filepath.Join(dir, "claude")
+	content := fmt.Sprintf("#!/bin/sh\ncat %q\nexit %d\n", outputFile, exitCode)
+	if err := os.WriteFile(script, []byte(content), 0755); err != nil {
+		t.Fatal(err)
+	}
+	return script
+}
+
 func TestValidateTask_Success(t *testing.T) {
 	srv, _ := testServer(t)