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, 38 insertions, 0 deletions

diff --git a/internal/api/events.go b/internal/api/events.go
new file mode 100644
index 0000000..eefe064
--- /dev/null
+++ b/internal/api/events.go
@@ -0,0 +1,38 @@
+package api
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/thepeterstone/claudomator/internal/event"
+)
+
+// handleListTaskEvents returns a task's observability event stream in seq order.
+// Pass ?since_seq=N to fetch only events newer than seq N (incremental polling).
+func (s *Server) handleListTaskEvents(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if _, err := s.store.GetTask(id); err != nil {
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": "task not found"})
+		return
+	}
+
+	var sinceSeq int64
+	if v := r.URL.Query().Get("since_seq"); v != "" {
+		n, err := strconv.ParseInt(v, 10, 64)
+		if err != nil || n < 0 {
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid since_seq"})
+			return
+		}
+		sinceSeq = n
+	}
+
+	events, err := s.store.ListEvents(id, sinceSeq)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+		return
+	}
+	if events == nil {
+		events = []*event.Event{}
+	}
+	writeJSON(w, http.StatusOK, events)
+}