feat: initial llm-chat v0.1.0 (llm.chat@0.1.0)

Generic Ollama-compatible LLM chat adapter. The lower-level
counterpart to orchestrator-llm: orchestrator-llm wraps the LLM
in a planning prompt that emits a structured F∆I Plan; this
module is the plain-prompt adapter that flows compose for
summarisation, translation, free-form Q&A, etc.

Capability surface:

  Inputs:
    prompt        : text
    endpoint      : text   (Ollama /api/chat URL)
    model         : text
    api_key       : text   (optional bearer token)
    system_prompt : text   (optional)

  Outputs:
    response       : text   (assistant reply)
    model_endpoint : text   (audit correlation)
    model_name     : text   (audit correlation)
    model_digest   : text   (Ollama /api/show probe; empty
                              for non-Ollama or transient failures)

  Permissions: net to localhost / 127.0.0.1 / api.openai.com /
               api.anthropic.com.

The audit-field trio (endpoint + name + digest) closes the same
forensic gap that orchestrator-llm v0.3.1 closed for plan
generation: any historical chat invocation can be traced to the
exact model that produced it.

Implementation reuses the same defensive Ollama client pattern
from orchestrator-llm — derive_show_url + extract_show_digest
+ best-effort probe_model_digest. Duplication accepted at the
two-module mark; a shared crate refactor lands once a third
module needs the same plumbing.

12 host-side tests cover prompt building, Ollama-shaped
response parsing, URL transform, digest extraction (top-level
+ nested), end-to-end success, end-to-end probe-failure
swallow, end-to-end skip-for-non-Ollama, and the missing-input
guards.

Wasm artifact: 294 KB. Verified to build with v1.0 fai:platform
imports baked in.

Bootstrapped via 'fai new module llm.chat' (workspace v0.10.13)
which now produces an SDK-based template directly.

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

module.yaml

@@ -0,0 +1,54 @@
+schema_version: 1
+name: llm-chat
+version: 0.1.0
+
+# Capability provided by this module.
+provides:
+  - capability: llm.chat
+    version: 0.1.0
+
+# Inputs the invoke function accepts.
+inputs:
+  # The user-facing prompt text.
+  prompt: text
+  # Ollama-shaped /api/chat endpoint, e.g.
+  # "http://localhost:11434/api/chat".
+  endpoint: text
+  # Model identifier as registered with the endpoint, e.g.
+  # "qwen2.5:14b" or "llama3.1:8b".
+  model: text
+  # Optional bearer token for cloud-hosted endpoints. Empty
+  # string means no Authorization header is sent.
+  api_key: text
+  # Optional system prompt. Empty string omits the system
+  # message and lets the model use its built-in default.
+  system_prompt: text
+
+# Outputs produced.
+outputs:
+  # The assistant's plain-text reply.
+  response: text
+  # The endpoint the response was generated against. Used for
+  # audit correlation.
+  model_endpoint: text
+  # The model identifier as supplied to the LLM API.
+  model_name: text
+  # SHA-256 digest of the served Ollama model, when reachable.
+  # Empty for non-Ollama endpoints (OpenAI / Anthropic do not
+  # expose a digest API). Together with model_endpoint and
+  # model_name this answers the audit question "which exact
+  # model produced this response?"
+  model_digest: text
+
+# Permissions required.
+#
+# The module makes outbound HTTP to the configured endpoint.
+# Default declarations cover loopback (Ollama) and the common
+# cloud providers. Operators with different endpoints fork
+# module.yaml in Phase 0.5; operator-config-driven permission
+# overrides arrive in Phase 1+.
+permissions:
+  - "net: localhost"
+  - "net: 127.0.0.1"
+  - "net: api.openai.com"
+  - "net: api.anthropic.com"