docs: add MODULE.md + MODULE.de.md inline docs

Explains the 'why this module instead of inline HTTP' answer
operators ask when they see llm.chat for the first time:
audit, permission posture, endpoint portability.

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

MODULE.md

@@ -0,0 +1,104 @@
+# llm.chat
+
+Generic Ollama-compatible LLM chat adapter. The building-block
+module any flow uses when it needs a one-shot LLM completion —
+classify, extract-fields, rewrite, decide — instead of rolling
+its own HTTP client.
+
+## Capability
+
+- `llm.chat@0.1.0`
+
+## Inputs
+
+| Name             | Type | Description                                                     |
+| ---------------- | ---- | --------------------------------------------------------------- |
+| `prompt`         | text | The user-facing prompt.                                         |
+| `endpoint`       | text | Ollama-shaped `/api/chat` URL (e.g. `http://localhost:11434/api/chat`). |
+| `model`          | text | Model identifier (e.g. `qwen2.5:14b`, `llama3.1:8b`).           |
+| `api_key`        | text | Optional bearer token for cloud-hosted endpoints.               |
+| `system_prompt`  | text | Optional system message. Empty = use the model's default.       |
+
+## Outputs
+
+| Name             | Type | Description                                                         |
+| ---------------- | ---- | ------------------------------------------------------------------- |
+| `response`       | text | The assistant's plain-text reply.                                   |
+| `model_endpoint` | text | The endpoint the response was generated against.                    |
+| `model_name`     | text | The model identifier as supplied to the LLM API.                    |
+| `model_digest`   | text | SHA-256 digest of the served Ollama model. Empty for cloud APIs.    |
+
+Together the three `model_*` outputs answer the audit
+question: "which exact model produced this response?" — that
+audit trail is the reason flows use this module rather than
+spawning their own HTTP calls.
+
+## Permissions
+
+```yaml
+permissions:
+  - "net: localhost"
+  - "net: 127.0.0.1"
+  - "net: api.openai.com"
+  - "net: api.anthropic.com"
+```
+
+Loopback (local Ollama) by default. Cloud endpoints require an
+operator-policy override in `~/.fai/config.yaml#security.max_permissions`.
+
+## Why this module instead of inline HTTP
+
+Three reasons:
+
+1. **Audit.** Every LLM call surfaces `model_endpoint`,
+   `model_name`, `model_digest` as separate outputs that land
+   in the hash-chained audit log alongside the response. A
+   regulator-facing reproducibility check just compares the
+   digest field to the model snapshot.
+2. **Permission posture.** The operator sees `llm.chat` in
+   the installed modules + its declared `net:` list. A
+   home-grown HTTP module would either hide its endpoints
+   or be a fresh review surface every time.
+3. **Endpoint portability.** The endpoint + model are flow
+   inputs, not compile-time constants. The same flow runs
+   against `localhost:11434` in dev and a production
+   inference cluster in prod just by swapping the input.
+
+## Limits in v0.1.0
+
+- No streaming. The whole reply is buffered before the output
+  step fires.
+- No tool-call / function-call surface. A flow needing tool
+  use composes multiple `llm.chat` steps with prompt
+  engineering, or uses MCP via the bridge.
+- Cloud-provider adapters for OpenAI and Anthropic are
+  deferred until a flow actually needs them. Today the
+  Ollama wire-format is the only target.
+
+## Example flow
+
+```yaml
+name: classify-incoming
+inputs:
+  text: text
+steps:
+  - id: classify
+    use: llm.chat@^0
+    with:
+      prompt: $inputs.text
+      system_prompt: |
+        Classify the text as one of: question, complaint,
+        feedback, spam. Answer with the label only.
+      endpoint: "http://localhost:11434/api/chat"
+      model: "qwen2.5:14b"
+outputs:
+  category: $classify.response
+  audit_model: $classify.model_digest
+```
+
+## Build
+
+```bash
+cargo build --release --target wasm32-wasip2
+# Output: target/wasm32-wasip2/release/llm_chat.wasm
+```