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/.

app/config.py

@@ -11,10 +11,19 @@ from functools import lru_cache
 from pydantic import field_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
-#: The A9 import formats (PLAN anchor A9, revised 2026-08-21).
-#: ``BOR_IMPORT_EXTENSIONS`` may narrow — but never widen — this set.
+#: The A9 import formats (PLAN anchor A9, revised 2026-08-21; revised
+#: 2026-08-27, owner permission — the full Podman quadlet family
+#: ``container, network, volume, image, pod, kube, swap, os, endpoint``
+#: plus Jinja templates ``j2`` join the allowed set, chunked as plain
+#: text). ``BOR_IMPORT_EXTENSIONS`` may narrow — but never widen — this
+#: set.
 _ALLOWED_IMPORT_EXTENSIONS: frozenset[str] = frozenset(
-    {"md", "markdown", "txt", "yaml", "yml", "json", "py"}
+    {
+        "md", "markdown", "txt", "yaml", "yml", "json", "py",
+        # A9 revised 2026-08-27 (owner permission): quadlet family + jinja.
+        "container", "network", "volume", "image", "pod",
+        "kube", "swap", "os", "endpoint", "j2",
+    }
 )
 
 
@@ -127,14 +136,17 @@ class Settings(BaseSettings):
     session_max_age: int = 43_200
     session_cookie: str = "bor_session"
 
-    # --- Import scope (A9, revised 2026-08-21) ---
+    # --- Import scope (A9, revised 2026-08-21 and 2026-08-27) ---
     # Comma-separated list of lowercased file extensions (no dot) imported
     # by ``scripts/import_docs.py``. Hidden (dot) path components are always
     # skipped, plus the importer's exclusion list.
     # Stored as a raw CSV string (env-native — no JSON) and parsed on demand
     # via :py:meth:`import_extension_set`. ``mode="after"`` validation runs
     # against the raw string so a typo fails loudly at startup.
-    import_extensions: str = "md,markdown,txt,yaml,yml,json,py"
+    import_extensions: str = (
+        "md,markdown,txt,yaml,yml,json,py,"
+        "container,network,volume,image,pod,kube,swap,os,endpoint,j2"
+    )
     #: List of git repo URLs to clone/pull into ``sources_dir`` before
     #: indexing (phase 28); comma-separated, stored raw. Empty means no git
     #: sources — ``import_docs`` then falls back to ``--source`` / the old