feat: OIDC/LDAP auth, audit log, maintenance windows, migrations

- Add OIDC (OpenID Connect) authentication with discovery URL support,
  group-based role mapping, and token introspection
- Add LDAP authentication with bind credentials, group-based role
  mapping, and configurable attribute names
- Add audit log (model, routes, templates) tracking settings changes,
  plugin enable/disable, login events
- Add migrations 0009 (widget variants), 0010 (maintenance windows),
  0011 (audit log)
- Add optional dependency groups to pyproject.toml: [ldap], [snmp]
- Add Settings → Auth tab with OIDC and LDAP configuration forms

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

fabledscryer/migrations/versions/0009_widget_variants.py

@@ -0,0 +1,26 @@
+"""Widget variants — add config_json and title to dashboard_widgets
+
+Revision ID: 0009_widget_variants
+Revises: 0008_share_tokens
+Create Date: 2026-03-22
+"""
+from typing import Sequence, Union
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "0009_widget_variants"
+down_revision: Union[str, None] = "0008_share_tokens"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column("dashboard_widgets",
+                  sa.Column("title", sa.String(128), nullable=True))
+    op.add_column("dashboard_widgets",
+                  sa.Column("config_json", sa.Text, nullable=True))
+
+
+def downgrade() -> None:
+    op.drop_column("dashboard_widgets", "config_json")
+    op.drop_column("dashboard_widgets", "title")

fabledscryer/migrations/versions/0010_maintenance_windows.py

@@ -0,0 +1,32 @@
+"""Maintenance windows for alert suppression
+
+Revision ID: 0010_maintenance_windows
+Revises: 0009_widget_variants
+Create Date: 2026-03-22
+"""
+from typing import Sequence, Union
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "0010_maintenance_windows"
+down_revision: Union[str, None] = "0009_widget_variants"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "maintenance_windows",
+        sa.Column("id", sa.String(36), primary_key=True),
+        sa.Column("name", sa.String(128), nullable=False),
+        sa.Column("start_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("end_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("scope_source", sa.String(64), nullable=True),
+        sa.Column("scope_resource", sa.String(255), nullable=True),
+        sa.Column("created_by", sa.String(36), sa.ForeignKey("users.id", ondelete="RESTRICT"), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("maintenance_windows")

fabledscryer/migrations/versions/0011_audit_log.py

@@ -0,0 +1,35 @@
+"""Audit log table
+
+Revision ID: 0011_audit_log
+Revises: 0010_maintenance_windows
+Create Date: 2026-03-22
+"""
+from typing import Sequence, Union
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "0011_audit_log"
+down_revision: Union[str, None] = "0010_maintenance_windows"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "audit_events",
+        sa.Column("id", sa.String(36), primary_key=True),
+        sa.Column("timestamp", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("user_id", sa.String(36),
+                  sa.ForeignKey("users.id", ondelete="SET NULL"), nullable=True),
+        sa.Column("username", sa.String(64), nullable=False, server_default="system"),
+        sa.Column("action", sa.String(64), nullable=False),
+        sa.Column("entity_type", sa.String(64), nullable=True),
+        sa.Column("entity_id", sa.String(255), nullable=True),
+        sa.Column("detail_json", sa.Text, nullable=True),
+    )
+    op.create_index("ix_audit_events_timestamp", "audit_events", ["timestamp"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_audit_events_timestamp", "audit_events")
+    op.drop_table("audit_events")