feat: Grafana-Panel Planung nach Kategorie inkl. Kreditraten (A11-T3)

Neue Tabelle planning_monthly (Monatssummen je Kategorie aus wiederkehrenden
Posten, Einmalposten und allen Kreditraten), Service planning_chart mit
refresh_planning_chart (Advisory-Lock, komplette Neuschreibung), GUI-Hooks
in index/planung_page ueber _safe_refresh, neues Barchart-Panel im
Grafana-Dashboard (Panel 5).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

finance/alembic/versions/d5e8b3c7a410_planning_monthly.py

@@ -0,0 +1,30 @@
+"""planning_monthly (Grafana-Panel Planung nach Kategorie)
+
+Revision ID: d5e8b3c7a410
+Revises: c4d7e2a91b53
+Create Date: 2026-09-28
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = 'd5e8b3c7a410'
+down_revision: Union[str, Sequence[str], None] = 'c4d7e2a91b53'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        'planning_monthly',
+        sa.Column('month', sa.Date(), primary_key=True),
+        sa.Column('category', sa.String(length=100), primary_key=True),
+        sa.Column('total', sa.Numeric(precision=12, scale=2), nullable=False),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table('planning_monthly')