chore(profile): drop dead curator columns from UserProfile

Drift-audit Group 7: learned_summary, observations_raw, and
observations_updated_at were populated by the curator/LLM-profile machinery
removed in the Phase-8 pivot. Nothing has written them since and the profile
API returned permanently-empty fields. Remove them from the model + to_dict
and drop the columns (migration 0062). Verified zero frontend/backend/test
consumers.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/fabledassistant/models/user_profile.py

@@ -1,6 +1,4 @@
-from datetime import datetime
-
-from sqlalchemy import DateTime, ForeignKey, Integer, Text
+from sqlalchemy import ForeignKey, Integer, Text
 from sqlalchemy.dialects.postgresql import ARRAY, JSONB
 from sqlalchemy.orm import Mapped, mapped_column
 
@@ -27,13 +25,6 @@ class UserProfile(Base, TimestampMixin):
     interests: Mapped[list[str] | None] = mapped_column(ARRAY(Text), nullable=True)
     # {days: ["Mon","Tue",...], start: "09:00", end: "17:00"}
     work_schedule: Mapped[dict | None] = mapped_column(JSONB, nullable=True)
-    # LLM-consolidated summary of learned preferences
-    learned_summary: Mapped[str | None] = mapped_column(Text, nullable=True)
-    # [{date: "YYYY-MM-DD", bullets: "..."}, ...]
-    observations_raw: Mapped[list | None] = mapped_column(JSONB, nullable=True)
-    observations_updated_at: Mapped[datetime | None] = mapped_column(
-        DateTime(timezone=True), nullable=True
-    )
 
     def to_dict(self) -> dict:
         return {
@@ -45,11 +36,4 @@ class UserProfile(Base, TimestampMixin):
             "tone": self.tone or "casual",
             "interests": self.interests or [],
             "work_schedule": self.work_schedule or {},
-            "learned_summary": self.learned_summary or "",
-            "observations_count": len(self.observations_raw or []),
-            "observations_updated_at": (
-                self.observations_updated_at.isoformat()
-                if self.observations_updated_at
-                else None
-            ),
         }