fix(commandcode): preserve images and reasoning_effort on /alpha/generate

Command Code dropped vision and ignored client effort through the router:
image blocks became "[image omitted]", HTTP image URLs were never inlined,
and reasoning_effort landed on the envelope wrapper instead of params (so the
DeepSeek family mapping remapped low -> high). The catalog also treated
deepseek/deepseek-v4.1-flash as text-only, so the vision adapter stole those
requests to another provider.

- Map OpenAI image_url / Claude image blocks (base64 or data-URI) to the
  native {type:"image", image:"data:...;base64,...", mimeType} generate block.
- Add FORMATS.COMMANDCODE to TARGETS_NEED_BASE64 so remote http(s) images are
  inlined by the existing SSRF-safe fetcher before translation.
- Write reasoning_effort inside params for targetFormat commandcode and pass
  low|medium|high|xhigh|max through unmapped; allow it in thinkingLevels.
- Provider-scoped capabilities for commandcode/cmc: vision except the CLI
  text-only denylist, thinkingFormat commandcode, so family patterns
  (deepseek-v4 -> thinkingFormat deepseek, vision false) no longer win.
- Quota Tracker: whoami + billing credits/subscriptions (credits vs plan cap,
  5h and weekly windows), labels from AI_PROVIDERS[].name.

open-sse/translator/concerns/prefetch.js

@@ -8,6 +8,7 @@ import { fetchImageAsBase64, parseDataUri } from "./image.js";
 const TARGETS_NEED_BASE64 = new Set([
   FORMATS.GEMINI, FORMATS.GEMINI_CLI, FORMATS.VERTEX,
   FORMATS.ANTIGRAVITY, FORMATS.OLLAMA, FORMATS.KIRO,
+  FORMATS.COMMANDCODE,
 ]);
 
 function isRemoteUrl(url) {