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