feat: scaffold tolkien v0 — local-LLM classifier wrapper + CLI + eval

Initial skeleton for the deterministic compound-AI pipeline that turns
`tolkien deploy <name>` into a valinor scaffold. v0 wires one classifier
(`db_kind`) end-to-end against the Ollama-on-radagast backend so we can
iterate prompts with confidence before adding the rest.

- pyproject.toml: uv project, Python 3.13, httpx/pydantic/typer/pyyaml.
- src/tolkien/llm.py: single-turn /api/chat wrapper. JSON-mode + temp 0 +
  30m keep-alive. Pydantic schema validation on parse.
- src/tolkien/cli.py: `tolkien classify db-kind --doc <file>` runs the
  classifier and prints JSON. `tolkien deploy <name>` is stubbed.
- src/tolkien/prompts/db_kind.md: tight system prompt with 1-shot example
  and explicit "return ONLY JSON" guard.
- src/tolkien/schemas.py: DbKindResult pydantic model.
- eval/cases/mealie.yml + run_eval.py: regression harness. Currently
  one case (mealie); failures print field-level diffs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

eval/cases/mealie.yml

@@ -0,0 +1,36 @@
+# Eval case for the `db_kind` classifier.
+# The pipeline's correctness on real apps is gated on this kind of fixture —
+# re-run `eval/run_eval.py` after every prompt change.
+
+name: mealie
+input: |
+  App: mealie (recipe manager). Excerpt from official docker-compose docs:
+
+  environment:
+    DB_ENGINE: postgres
+    POSTGRES_USER: mealie
+    POSTGRES_PASSWORD: change-me
+    POSTGRES_SERVER: postgres
+    POSTGRES_PORT: 5432
+    POSTGRES_DB: mealie
+    ALLOW_SIGNUP: "true"
+    BASE_URL: https://mealie.example.com
+    OPENAI_API_KEY: sk-...      # optional, enables recipe parsing via OpenAI
+    TZ: Europe/Amsterdam
+
+expected:
+  needs_postgres: true
+  db_env_vars:
+    - DB_ENGINE
+    - POSTGRES_USER
+    - POSTGRES_PASSWORD
+    - POSTGRES_SERVER
+    - POSTGRES_PORT
+    - POSTGRES_DB
+  secrets:
+    - POSTGRES_PASSWORD
+    - OPENAI_API_KEY
+  config:
+    - ALLOW_SIGNUP
+    - BASE_URL
+    - TZ

eval/run_eval.py

@@ -0,0 +1,70 @@
+"""Run all eval cases and report which pass/fail.
+
+Each case has a `name`, an `input` string, and an `expected` dict. The current
+v0 only exercises the `db_kind` classifier. As more classifiers come online,
+each case will grow expected sections for them too.
+
+Run from the repo root:
+
+    uv run python eval/run_eval.py
+"""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+import yaml
+
+from tolkien.llm import classify
+from tolkien.schemas import DbKindResult
+
+CASES_DIR = Path(__file__).parent / "cases"
+
+
+def _diff_fields(expected: dict, actual: dict) -> list[str]:
+    """Return human-readable lines describing field-level mismatches."""
+    diffs: list[str] = []
+    for key, want in expected.items():
+        got = actual.get(key)
+        if isinstance(want, list) and isinstance(got, list):
+            want_set, got_set = set(want), set(got)
+            missing = want_set - got_set
+            extra = got_set - want_set
+            if missing or extra:
+                diffs.append(f"  {key}: missing={sorted(missing)} extra={sorted(extra)}")
+        elif want != got:
+            diffs.append(f"  {key}: want={want!r} got={got!r}")
+    return diffs
+
+
+def main() -> int:
+    cases = sorted(CASES_DIR.glob("*.yml"))
+    if not cases:
+        print(f"No cases found in {CASES_DIR}", file=sys.stderr)
+        return 2
+
+    failures = 0
+    for case_path in cases:
+        case = yaml.safe_load(case_path.read_text())
+        name = case["name"]
+        result = classify("db_kind", case["input"], DbKindResult)
+        actual = result.model_dump()
+        diffs = _diff_fields(case["expected"], actual)
+        if diffs:
+            failures += 1
+            print(f"FAIL {name}")
+            for line in diffs:
+                print(line)
+        else:
+            print(f"PASS {name}")
+
+    if failures:
+        print(f"\n{failures}/{len(cases)} cases failed.", file=sys.stderr)
+        return 1
+    print(f"\nAll {len(cases)} cases passed.")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())