feat(db): migration 0040 — rename briefing_date to day_date, hard cut briefing data

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

alembic/versions/0040_rename_briefing_date_drop_briefing_data.py

@@ -0,0 +1,26 @@
+"""rename briefing_date to day_date and drop existing briefing conversations
+
+Revision ID: 0040
+Revises: 0039
+Create Date: 2026-04-25
+
+This is a hard-cut migration accompanying the Journal feature. The user
+has accepted destruction of existing briefing data per the design spec.
+"""
+from alembic import op
+
+
+revision = "0040"
+down_revision = "0039"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.execute("DELETE FROM conversations WHERE conversation_type = 'briefing'")
+    op.alter_column("conversations", "briefing_date", new_column_name="day_date")
+    op.execute("DELETE FROM settings WHERE key = 'briefing_config'")
+
+
+def downgrade() -> None:
+    op.alter_column("conversations", "day_date", new_column_name="briefing_date")