feat(analytics): add PSA activity logging and enhanced PSA metrics endpoint

- Log `note_posted` and `time_entry_posted` activities to `psa_activity_logs`
  after each successful PSA push in `psa_documentation_service.py`; errors
  are caught and logged without blocking the main push flow
- Add `PsaFunnel`, `PsaDailyTrend`, and `EnhancedPsaMetrics` Pydantic schemas
- Add `GET /analytics/flowpilot/psa-metrics?period=30d` endpoint (team_admin,
  rate-limited 15/min) returning time entry totals, push funnel
  (sessions → linked → doc pushed → time entry logged), and daily trend

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/services/psa_documentation_service.py

@@ -14,6 +14,7 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.ai_session import AISession
+from app.models.psa_activity_log import PsaActivityLog
 from app.models.psa_connection import PsaConnection
 from app.models.psa_member_mapping import PsaMemberMapping
 from app.models.psa_post_log import PsaPostLog
@@ -303,6 +304,7 @@ async def push_documentation(
         )
 
         # Create time entry if member mapping exists
+        time_entry_hours: Optional[float] = None
         if member_mapping and session.resolved_at and session.created_at:
             try:
                 delta = session.resolved_at - session.created_at
@@ -316,10 +318,38 @@ async def push_documentation(
                         hours=rounded_hours,
                         notes=f"FlowPilot session: {session.problem_summary or 'Troubleshooting'}",
                     )
+                    time_entry_hours = rounded_hours
             except Exception as e:
                 logger.warning("Failed to create time entry for session %s: %s", session.id, e)
                 # Don't fail the note push just because time entry failed
 
+        # Log PSA activity — note posted
+        try:
+            note_activity = PsaActivityLog(
+                account_id=session.account_id,
+                session_id=session.id,
+                activity_type="note_posted",
+                hours_logged=None,
+                psa_ticket_id=session.psa_ticket_id,
+            )
+            db.add(note_activity)
+        except Exception as e:
+            logger.warning("Failed to log PSA note activity for session %s: %s", session.id, e)
+
+        # Log time entry activity if one was created
+        if time_entry_hours is not None:
+            try:
+                time_activity = PsaActivityLog(
+                    account_id=session.account_id,
+                    session_id=session.id,
+                    activity_type="time_entry_posted",
+                    hours_logged=time_entry_hours,
+                    psa_ticket_id=session.psa_ticket_id,
+                )
+                db.add(time_activity)
+            except Exception as e:
+                logger.warning("Failed to log PSA time entry activity for session %s: %s", session.id, e)
+
         # Log success
         log_entry = PsaPostLog(
             id=uuid.uuid4(),