feat(import): index quadlet unit files and jinja templates (A9 revision)

Phase 47 (owner permission 2026-08-27, TODO.md L10–11, roadmap R1): the
full Podman quadlet family (.container, .network, .volume, .image,
.pod, .kube, .swap, .os, .endpoint) and .j2 Jinja templates join the
allowed + default A9 import formats, chunked as plain text (owner
decision — no TOML/Jinja-aware splitter). No env configuration needed:
a default import now indexes them.

- app/config.py: _ALLOWED_IMPORT_EXTENSIONS + the default
  import_extensions CSV gain the ten names (the original seven first);
  the never-widen BOR_IMPORT_EXTENSIONS validator is untouched and
  still rejects truly unknown extensions.
- app/rag/chunker.py: ten _FORMAT_CHUNKERS entries -> chunk_text
  (HARD_MAX_CHARS 1200 honored, unknown-suffix fallback unchanged);
  docstring/comments cite the A9 revision 2026-08-27.
- tests/fixtures/docs/homelab/: quadlet/compose.container (realistic
  quadlet TOML, >1500 chars, [Unit]/[Service]/[Container] sections,
  RESE-QUADLET-SENTINEL-77aa), quadlet/lan.network,
  quadlet/cache.volume, templates/deploy.j2 (for/set/if Jinja
  constructs + RESE-JINJA-SENTINEL-33dd). Every suite that seeds the
  fixture tree updates its 9 -> 13 document-count constants.
- tests/unit/test_config.py: allowed set carries all seventeen formats,
  default CSV + dotted import_extension_set include the ten, the
  validator accepts the new names and still rejects unknowns.
- tests/unit/test_chunker.py: dispatch parity with chunk_text for every
  new suffix (parametrized), the .container fixture chunks >=2 under
  the cap with the sentinel surviving, the .j2 fixture keeps {{ }}
  verbatim, the unknown-suffix fallback is unchanged.
- tests/unit/test_importer.py: a default-extensions walk over a temp
  tree indexes exactly the ten new files (unknown/hidden/excluded
  filtered), the original seven still walk, stem-title fallback holds.
- tests/integration/test_import_quadlet_jinja.py (new): import_sources
  over a temp tree with .container/.volume/.j2 -> documents + chunks
  rows with stem titles; delta re-import updates only the changed .j2
  doc; prune drops the deleted .volume doc with cascade.
- tests/e2e/test_quadlet_jinja_import.py (new, story suite, mock-only,
  isolation): GET /api/docs (admin session) lists the four new-format
  docs with non-zero chunk counts and stem titles; the Sources table
  renders a row + .doc-link per file; the phase-26 modal shows the
  .container TOML ([Container] section + sentinel) with stem title and
  the container format badge; a RESE-JINJA-SENTINEL-33dd question
  FTS-matches the .j2 chunk -> honest-positive (A8: LOW requires zero
  FTS hits) — the bubble is not .is-deflected and a source chip names
  templates/deploy.j2.
- README.md + .env.example: the extended default format set (A9
  revised 2026-08-27, plain-text chunking, narrow-only rule intact).
- .agent/PLAN.md: the A9 revision (owner-locked R1) — A9 row status,
  the revision note under the anchors table, and the §5 chunking-policy
  + §11 workflow lines. The only PLAN edit this phase.

Gates: uv run pytest 795 passed; app/ coverage TOTAL 99% (>90%);
ruff check + pyright clean; story E2E 4/4 in isolation (DB up);
regression E2E suites test_import_documents (3) / test_sync_button
(3) / test_git_sources_admin (6) green in isolation.

Also records the 47_quadlet_jinja_import task-file moves (01–03)
todo/ -> complete/.

tests/e2e/test_sources_midstream_bug.py

@@ -154,11 +154,11 @@ def _no_error_banner(page: Page) -> None:
 
 @pytest.fixture()
 def seeded_kb(mock_llm: int, db_ready: None) -> Iterator[None]:
-    """A fresh KB seeded from ``tests/fixtures/docs`` (9 docs since phase
-    44, A9 formats), truncated again on teardown. ``db_ready`` (conftest)
+    """A fresh KB seeded from ``tests/fixtures/docs`` (13 docs since phase
+    47, A9 formats), truncated again on teardown. ``db_ready`` (conftest)
     skips with clear instructions when Postgres is down."""
     summary = _reset_db(mock_llm, seed=True)
-    assert summary is not None and summary.added == 9
+    assert summary is not None and summary.added == 13
     yield
     _reset_db(mock_llm, seed=False)