feat: Core Plugin system — is_core flag, topological sort dependency resolution, deactivation protection

alembic/versions/0016_plugin_is_core.py

@@ -0,0 +1,45 @@
+"""Add is_core boolean column to plugins table.
+
+Marks core plugins (permissions, entity_links, tags) as is_core=True so they
+cannot be deactivated and are always loaded first.
+
+Revision ID: 0016_plugin_is_core
+Revises: 0015_rls_policies
+Create Date: 2026-07-07
+"""
+
+from __future__ import annotations
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "0016_plugin_is_core"
+down_revision: Union[str, None] = "0015_rls_policies"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+CORE_PLUGIN_NAMES = ["permissions", "entity_links", "tags"]
+
+
+def upgrade() -> None:
+    # Add is_core column with server default False so existing rows get False
+    op.add_column(
+        "plugins",
+        sa.Column("is_core", sa.Boolean(), nullable=False, server_default=sa.text("false")),
+    )
+
+    # Mark known core plugins as is_core=True
+    op.execute(
+        sa.text(
+            "UPDATE plugins SET is_core = true WHERE name IN :names"
+        ).bindparams(sa.bindparam("names", expanding=True)).bindparams(names=CORE_PLUGIN_NAMES)
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("plugins", "is_core")