feat(sources): admin page to add and remove git sources (TODO.md L4)

alembic/versions/0006_git_sources.py

@@ -0,0 +1,48 @@
+"""git sources: admin-managed list of git repo URLs
+
+Revision ID: 0006
+Revises: 0005
+Create Date: 2026-08-26
+
+Phase 35 (git-sources-admin story, A13 — one additive, reversible table,
+no other schema change):
+
+* ``git_sources`` — one row per admin-managed git source URL. The admin
+  page (``/git-sources.html``) maintains the list that the Sync button
+  (phase 32) and ``import_docs`` (phase 28) clone/pull. DB rows win over
+  the ``BOR_GIT_SOURCES`` env var, which stays a fallback while the table
+  is empty (once the table has rows it is ignored — the UI is the source
+  of truth). ``url`` is unique (``uq_git_sources_url``); ``added_at`` is
+  stamped server-side and orders the list oldest-first.
+"""
+from __future__ import annotations
+
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+from alembic import op
+
+revision = "0006"
+down_revision = "0005"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "git_sources",
+        sa.Column("id", postgresql.UUID(as_uuid=True), primary_key=True),
+        sa.Column("url", sa.Text(), nullable=False),
+        sa.Column(
+            "added_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+    op.create_index("uq_git_sources_url", "git_sources", ["url"], unique=True)
+
+
+def downgrade() -> None:
+    op.drop_index("uq_git_sources_url", table_name="git_sources")
+    op.drop_table("git_sources")