feat: sync log, cache clear endpoint, Todoist projects from cached tasks

- migration 016: sync_log table
- store: AddSyncLogEntry, GetRecentSyncLog, InvalidateAllCaches, GetProjectsFromTasks
- settings: HandleClearCache (POST /settings/clear-cache), SyncLog in page data
- settings: use GetProjectsFromTasks instead of deprecated Todoist REST /projects
- handlers: populate atom projects from store
- agent: log warning on registration failure instead of silently swallowing
- google_tasks: simplify URL literal
- tests: sync log CRUD, clear cache handler, settings page includes sync log,
  sync sources adds log entry, incremental sync paths, task completion
  response/headers, calendar cache fallback

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

1 files changed, 3 insertions, 2 deletions

diff --git a/internal/handlers/agent.go b/internal/handlers/agent.go
index b285520..aa3f000 100644
--- a/internal/handlers/agent.go
+++ b/internal/handlers/agent.go
@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/base64"
 	"encoding/json"
+	"log"
 	"net/http"
 	"time"
 
@@ -253,8 +254,8 @@ func (h *Handler) HandleAgentAuthApprove(w http.ResponseWriter, r *http.Request)
 
 	// Register/update agent in the trusted agents table
 	if err := h.store.CreateOrUpdateAgent(session.AgentName, session.AgentID); err != nil {
-		// Log but don't fail - the session was approved
-		// This just affects future trust level checks
+		// Don't fail - the session was approved; this just affects future trust level checks
+		log.Printf("warning: failed to register agent %q: %v", session.AgentName, err)
 	}
 
 	w.Header().Set("Content-Type", "application/json")