Fix 422 on agent trigger: accept plural data type names

AgentTriggerRequest.what_to_extract now accepts list[str] instead of
strict Literal values. _to_data_types normalises all FE variants
(tasks/task, notes/note, timelines/timeline/timelineEvents,
projects/project) to the canonical plural form the runner expects,
with deduplication.

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

app/api/routes/agents.py

@@ -49,12 +49,19 @@ def _dt_ms_opt(dt: datetime | None) -> int | None:
 
 def _to_data_types(values: list[str]) -> list[str]:
     normalize = {
-        "task": "tasks",
-        "note": "notes",
-        "timeline": "timelines",
-        "project": "projects",
+        "task": "tasks",           "tasks": "tasks",
+        "note": "notes",           "notes": "notes",
+        "timeline": "timelines",   "timelines": "timelines",   "timelineEvents": "timelines",
+        "project": "projects",     "projects": "projects",
     }
-    return [normalize[v] for v in values if v in normalize]
+    seen: set[str] = set()
+    result: list[str] = []
+    for v in values:
+        mapped = normalize.get(v)
+        if mapped and mapped not in seen:
+            seen.add(mapped)
+            result.append(mapped)
+    return result
 
 
 def _to_run_log_response(log: AgentRunLog) -> AgentRunLogResponse: