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

app/rag/git_sources.py

@@ -0,0 +1,44 @@
+"""The shared git-source resolver (phase 35, task 03).
+
+One function, two callers: the in-app Sync pipeline
+(``app/api/sync.py::_run_sync``) and the CLI
+(``scripts/import_docs.py::_resolve_sources``) — both resolve the repo
+URLs to clone/pull through :func:`effective_git_sources`, so the
+admin-managed ``git_sources`` table is what actually gets cloned and
+indexed from either entry point (the API's ``GET /api/git-sources``
+fallback list is the only other place that reads the env list — task 02).
+
+Precedence (the phase's locked decision — the env var is demoted, not
+removed): ``git_sources`` DB rows win, in ``(added_at, id)`` order;
+``BOR_GIT_SOURCES`` is a fallback only while the table is empty; both
+empty → ``([], "env")`` and each caller keeps its existing fail-loud
+behavior (sync: ``GitSyncError``; CLI: the legacy ``DEFAULT_SOURCES``
+fallback).
+"""
+from __future__ import annotations
+
+from typing import Literal
+
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from app.config import get_settings
+from app.models import GitSource
+
+
+def effective_git_sources(db: Session) -> tuple[list[str], Literal["db", "env"]]:
+    """``(urls, origin)`` — the repo URLs to clone, and where they came from.
+
+    ``"db"``: the ``git_sources`` rows in ``(added_at, id)`` order (oldest
+    first, id tie-break for same-timestamp inserts) — once the table has
+    any row, ``BOR_GIT_SOURCES`` is ignored entirely.
+    ``"env"``: the ``BOR_GIT_SOURCES`` list — ``Settings.git_source_list``,
+    the phase-28 CSV parse, reused not re-implemented — used only while
+    the table is empty; both empty → ``([], "env")``.
+    """
+    rows = db.scalars(
+        select(GitSource).order_by(GitSource.added_at.asc(), GitSource.id.asc())
+    ).all()
+    if rows:
+        return [row.url for row in rows], "db"
+    return list(get_settings().git_source_list), "env"