Excise v0.3.0 — opt-in local-Ollama LLM rerank

[0.3.0] — 2026-05-23

Added

• Opt-in LLM rerank via local Ollama (--llm). Layers a local model on
  top of the v0.2 heuristic shortlist: heuristic stays the cheap pre-filter,
  LLM only judges that shortlist and writes a one-line reason per turn.
• New flags --llm, --llm-model, --llm-host on both suggest and pick.
• New optional config file excise.toml (./excise.toml → $XDG_CONFIG_HOME/excise/
  → ~/.config/excise/) with [llm] block: host, model, top_n, timeout_sec.
• internal/llm/ package (tiny Ollama HTTP client + rerank logic + hard-coded
  prompt template) and internal/config/ package (TOML loader with sane defaults).
• New testdata claude_session_llm_rerank.jsonl + cmd-level tests for the
  happy path, fallback path, and JSON-parse-failure path against a stubbed
  Reranker. Live-Ollama integration test gated behind EXCISE_LIVE_OLLAMA=1.

Changed

• suggest and pick route the heuristic shortlist through the LLM reranker
  when --llm is set. Exit codes unchanged: 0 on success (incl. graceful
  fallback), 2 only on usage error.
• TUI shows per-turn LLMReason next to pre-marked turns when present.

Fixed

• Test helper NewStubReranker was originally placed in _test.go (invisible
  across packages); moved to internal/llm/stub.go so cmd-level tests resolve.
• go.sum regenerated to match real BurntSushi/toml@v1.4.0 checksum.

Trust contract (unchanged from v0.1/v0.2)

• No outbound network beyond the user-configured Ollama host.
• No autocut. --llm only changes ranking; user still confirms every excision.
• No telemetry, no acceptance log, no cross-session learning.

Still out of scope

• Remote LLM API key backends (OpenAI / Anthropic / OpenRouter) — deferred to v0.4.
• Streaming LLM output / partial-rerank UI.
• LLM + autocut combination.
• User-editable prompt template.