feat(calendar): migration 0029 — add caldav_uid and color to events

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

alembic/versions/0029_add_calendar_columns.py

@@ -0,0 +1,19 @@
+"""Add caldav_uid and color columns to events table."""
+
+from alembic import op
+
+revision = "0029"
+down_revision = "0028"
+
+
+def upgrade() -> None:
+    op.execute("""
+        ALTER TABLE events
+            ADD COLUMN IF NOT EXISTS caldav_uid TEXT DEFAULT '',
+            ADD COLUMN IF NOT EXISTS color TEXT DEFAULT ''
+    """)
+
+
+def downgrade() -> None:
+    op.execute("ALTER TABLE events DROP COLUMN IF EXISTS color")
+    op.execute("ALTER TABLE events DROP COLUMN IF EXISTS caldav_uid")