phase: 102_extensionless_filenames

All verification complete — every gate green, no defects found in previously completed work.

**Phase 102 final verification pass — report**

Verified (all three task files present in `complete/`; working-tree implementation matches D1–D5 design):
- `match_extension` choke point in `app/rag/importer.py` (walk + `formats` counter), `doc_format` name-token badge in `app/api/docs.py`, config/`.env.example` docs, fixture `tests/fixtures/extensionless_kb/`, integration + E2E suites — all present and correct
- Completion criteria: end-to-end sync (✓ integration + E2E), case matrix incl. `mydockerfile`/`Dockerfile.dev`/`.dockerfile` exclusions (✓ unit), `formats=dockerfile:1` not `unknown` (✓ log-line assertion), badge `dockerfile`/`containerfile` + `text` fallback + suffixed unchanged (✓ unit/integration/E2E), prune-on-token-removal (✓ `pruned==2`), suffixed-path rule byte-identical (✓ single-line swap, existing cases untouched)

Test / lint results (exact commands):
- `uv run pytest --cov=app --cov-report=term-missing` → 2084 passed, **99%** coverage (>90% gate)
- `uv run pytest tests/e2e/test_extensionless_import.py -v --no-cov` → 2 passed, isolated, DB up
- Regressions isolated: `test_import_documents` 3✓, `test_import_extensions_env` 2✓, `test_quadlet_jinja_import` 4✓, `test_document_viewer` 7✓, `test_kb_tree` 8✓
- `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings

Notable: commit intentionally not made (harness commits the phase); 102's task files already sit in `complete/`, overview stays in `todo/` for the harness.
Next pending phases: 98, 99, 103, 104, 105 (numeric next after 102: `103_suggestions_session_openers`).

app/config.py

@@ -207,7 +207,10 @@ class Settings(BaseSettings):
     # doubles as the typo guard); the value below is the built-in default
     # (the A9 family, incl. the quadlet family + ``j2``) and the documented
     # example in ``.env.example``. Hidden (dot) path components are always
-    # skipped, plus the importer's exclusion list.
+    # skipped, plus the importer's exclusion list. A token also matches
+    # extensionless files whose lowercased full filename equals it exactly
+    # (``dockerfile`` → ``Dockerfile``), case-insensitive, no partial
+    # names (phase 102).
     # Stored as a raw CSV string (env-native — no JSON) and parsed on demand
     # via :py:meth:`import_extension_set`. The validator rejects an empty
     # list and malformed tokens so a typo fails loudly at startup (it can