feat: OpenAI and Anthropic wire-format adapters via new api input

New optional input api: ollama|openai|anthropic (default ollama —
existing flows unchanged).

- openai: OpenAI Chat Completions format (/v1/chat/completions),
  Bearer auth — targets vLLM and compatible self-hosted servers.
- anthropic: Messages API (/v1/messages), x-api-key +
  anthropic-version headers, top-level system field, mandatory
  max_tokens (fixed 4096).
- Audit outputs unchanged: model_endpoint/model_name always set;
  model_digest stays Ollama-only (no digest API on openai/anthropic,
  field is left empty rather than fabricated).
- api_key is only ever placed in auth headers; never in outputs,
  errors, or audit events (verified against the event log).
- No streaming, no tool calls.

Bump module + capability version to 0.2.0. Wire-format unit tests
for request serialization and response parsing against fixed JSON
fixtures; live smoke green on the ollama path and on the openai
path against an OpenAI-compatible local endpoint.

Signed-off-by: flemming-it <sf@flemming.it>

Cargo.toml

@@ -5,7 +5,7 @@
 
 [package]
 name = "llm_chat"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2024"
 license = "Apache-2.0"
 publish = false