feat: add API inference logging for debugging

[daniel-lxs]

Summary

Adds a lightweight logging system for API inference requests/responses across all providers, helping with debugging and understanding what data is being sent to/received from LLM providers.

Implementation

• Created ApiInferenceLogger singleton class in src/api/logging/ApiInferenceLogger.ts
• Added inferenceLogger property to BaseProvider
• Updated all providers to use the logger
• Logger is configured in extension.ts with output channel as sink

Features

• Logs request payloads (model, maxTokens, temperature, messageCount, etc.)
• Logs response payloads (text, reasoning, tool calls, usage)
• Payload sanitization:
  • Truncates long strings (>10k chars)
  • Caps arrays/objects (>200 items/keys)
  • Replaces base64 images with placeholders
  • Redacts secrets (apiKey, authorization, password, etc.)
• Enable via ROO_CODE_API_LOGGING=true environment variable

Output Example

[API][request]
{
  "provider": "Roo Code Cloud",
  "operation": "createMessage",
  "model": "anthropic/claude-opus-4.5",
  "taskId": "...",
  "requestId": "req_...",
  "timestamp": "...",
  "payload": { ... }
}
[API][response]
{
  "provider": "Roo Code Cloud",
  "durationMs": 5669,
  "payload": { "text": "...", "usage": { ... } }
}

Inspired by

#10176 - simplified the approach to use a logging class integrated into the base provider

Closes ROO-271

---

Important

Introduces ApiInferenceLogger for logging API inference requests/responses, integrated into all providers and configurable via environment variable.

• Behavior:
  • Adds ApiInferenceLogger singleton in ApiInferenceLogger.ts for logging API inference requests/responses.
  • Integrates logger into BaseProvider and updates all providers to use it.
  • Configures logger in extension.ts with output channel as sink.
• Features:
  • Logs request payloads (model, maxTokens, temperature, etc.) and response payloads (text, reasoning, tool calls, usage).
  • Sanitizes payloads by truncating long strings, capping arrays/objects, replacing base64 images, and redacting secrets.
  • Enabled via ROO_CODE_API_LOGGING=true environment variable.
• Misc:
  • Adds tests for ApiInferenceLogger in ApiInferenceLogger.spec.ts.
  • Updates provider classes like OpenAiHandler, OpenRouterHandler, and RooHandler to use the logger.

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[roomote]

Rooviewer   See task on Roo Cloud

All issues have been resolved. LGTM!

• anthropic.ts:382 - Replace confusing if (logHandle!) with standard if (logHandle) check

Previous reviews

• 4b525dc: Review #1
• 14bae05: Review #2

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}