feat: add standalone AI/Tech regime-change monitor tab

A new /regime tab scoring how far the AI/Tech bull regime has deteriorated
toward a re-rating as a single 0-100 index with per-signal breakdown and a
7/30-day trend. Intentionally decoupled: nothing reads its output to gate or
score trades — the daily-pipeline membership is scheduling only.

- regime_monitor_service: price sub-scores (P1-P6 via Alpaca, like
  market_regime), VIX + HY credit spreads via a small FRED helper, weighted
  aggregation over available signals (missing source -> n/a, dropped from the
  denominator), one snapshot row/day, and a ~90-day history backfill by
  replaying the already-fetched series as-of each past day.
- F1/F3 fundamentals proposed by the configured grounded LLM (reuses
  sentiment_provider_service config resolution), with a manual override + lock.
- regime_snapshots table (migration 011); endpoints on the existing market
  router; admin-editable weights/threshold; standalone /regime page.

Data needs: prices via Alpaca, VIX/credit via FRED (optional key — signals show
n/a without it). No LLM needed for history.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

alembic/versions/011_add_regime_snapshots.py

@@ -0,0 +1,43 @@
+"""add regime_snapshots table
+
+Stores the daily AI/Tech regime-change index (one row per date) so the monitor
+tab can show a 7/30-day trend. Standalone, observational feature: no other table
+or job reads this.
+
+Revision ID: 011
+Revises: 010
+Create Date: 2026-06-26 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "011"
+down_revision: Union[str, None] = "010"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "regime_snapshots",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("date", sa.Date(), nullable=False),
+        sa.Column("total_score", sa.Float(), nullable=False),
+        sa.Column("band", sa.String(length=20), nullable=False),
+        sa.Column("breakdown_json", sa.Text(), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(
+        "uq_regime_snapshots_date", "regime_snapshots", ["date"], unique=True
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("uq_regime_snapshots_date", table_name="regime_snapshots")
+    op.drop_table("regime_snapshots")