fix(usage): drop duplicated commandcode import and features block

The previous origin/master merges (11089ab1 and earlier) left two
auto-merged artifacts behind because both sides added the same lines in
different places:

- services/usage.js declared `getCommandCodeUsage` twice (import + handler),
  which is an ESM SyntaxError on a clean checkout. The working tree masked
  it, so `next build` passed locally while the committed tree did not parse.
- providers/registry/commandcode.js carried two `features` blocks; the
  second one shadowed the first for `usage`/`usageApikey`.

Verified with `node --check` on the committed blob.

open-sse/providers/registry/commandcode.js

@@ -38,10 +38,6 @@ export default {
       summaryUrl: "/alpha/usage/summary",
     },
   },
-  features: {
-    usage: true,
-    usageApikey: true,
-  },
   models: [
     { id: "deepseek/deepseek-v4-pro", name: "DeepSeek V4 Pro" },
     { id: "deepseek/deepseek-v4-flash", name: "DeepSeek V4 Flash" },