docs: align documentation with current implementation

[chensid]

Summary

• document the actual lazy-init observer defaults and latching semantics in the English and Chinese READMEs
• use the public LoadingOption type in the API tables and correct its ECharts 6.1 default-value documentation
• align the agent API quick reference with the implementation defaults

Why

The implementation had moved ahead of parts of the documentation: lazy-init fallback settings were implicit, loadingOption was described only as object, and loading colors still reflected older ECharts defaults. This keeps the published API docs and generated declaration comments consistent with the current code.

Impact

Documentation and type-comment corrections only; there is no runtime behavior change.

Validation

• CI=true vp install --frozen-lockfile
• vp check
• vp pack (publint + attw)
• vp test run --coverage — 294 passed, 1 skipped, 100% coverage
• vp run size

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (c23d381) to head (8a10911).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #513   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           20        20           
  Lines          648       648           
  Branches       151       151           
=========================================
  Hits           648       648           

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