fix(docs): run JSDoc once per documentation build

[ShiroKSH]

Description

Fixes #3957.

The JSDoc migration stopped passing the API directory to the documentation command but preserved the old per-directory loop. Since .jsdoc.js recursively reads all of build/src, every iteration regenerated the same documentation tree.

Impact

Documentation output is generated once from the same built source tree. This avoids 331 redundant JSDoc processes and concurrent writes to the shared docs/ directory.

Testing

• Compiled src/generator/docs.ts and test/test.docs.ts, then ran npx mocha build/test/test.docs.js.
• Ran npx eslint src/generator/docs.ts test/test.docs.ts.

Additional Information

No generated API clients or public API surface changed.

Checklist

• Opened docs generator runs JSDoc once per API directory #3957 before submitting the fix.
• Added a focused regression test for a single JSDoc invocation.
• Updated the affected JSDoc comment.
• Ran focused tests and lint for the changed files.

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