docs: resolve markdown lint errors in README.md (#799)

[fancyboi999]

Description

This PR addresses the CI/CD failures reported in #799 by systematically fixing all Markdown linting errors in README.md. The goal is to bring the file into full compliance with the project's .markdownlint.json rules.

Key Changes

Following the specific recommendations in Issue #799, I have implemented the following fixes:

1. HTML Removal (MD033 - Essential Fix):
   • Replaced all disallowed inline HTML tags (<div align="center">, <br>, <details>, <summary>, <kbd>, <strong>) with standard Markdown syntax.
   • Note: This change adheres to the "Replace or Remove Inline HTML" instruction in the issue, which prioritizes lint compliance over custom centering/folding layouts.
2. Line Length Control (MD013):
   • Manually reflowed long lines (including prompt examples and deep links) to stay within the 80-character limit.
3. Accessibility & Media (MD045):
   • Added descriptive alt text to all images and badges that previously lacked it.
4. Spacing & Structure (MD001, MD009, MD012, MD022, MD032):
   • Standardized heading increments (no skipping levels).
   • Ensured a single blank line surrounding all headings and lists.
   • Removed all trailing spaces and multiple consecutive empty lines.
5. URL & Table Formatting (MD034, MD060):
   • Wrapped bare URLs and email addresses in < >.
   • Re-aligned Markdown tables for consistent spacing and style.
6. Reference Cleanup (MD053):
   • Eliminated unused and duplicate link/image reference definitions.

Verification

I have verified the fix locally using markdownlint-cli.

• Command: npx markdownlint-cli README.md
• Result: 0 errors found (Exit Code 0).

Closings

Fixes #799

[fancyboi999]

Hi @Wendong-Fan @fengju0213,

I've fixed all Markdown linting errors in README.md to resolve #799.

Please note that per the project's strict MD033 (no-inline-html) rule and the instructions in the issue, I have removed the <div align="center"> tags. This means the layout is now left-aligned instead of centered, but it ensures the CI lint check passes successfully (already verified in GitHub Actions).

Ready for your review. Thanks!