feat: collapse older What's New entries by default

[zjowowen]

Show only the 2 most recent dates expanded, wrap older entries in a collapsible

Details

block. Updated the readme-whats-new workflow to apply this formatting automatically on each run.

Summary

Changes

Related Issues

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)

Checklist

• My code follows the project's coding style
• I have added tests that cover my changes (if applicable)
• All new and existing tests pass (npm test)
• Lint passes (npm run lint)
• I have updated the documentation (if applicable)
• I have checked that there are no sensitive data (API keys, tokens, etc.) in my changes

[Copilot]

Pull request overview

Updates the “What’s New” sections across the main README and localized docs so that only the two most recent dates are expanded by default, with older entries collapsed behind a <details> disclosure. Also updates the readme-whats-new GitHub Actions workflow to apply this formatting automatically after it appends new entries.

Changes:

• Wrapped older “What’s New” entries in a <details> block in README.md and localized READMEs.
• Updated the readme-whats-new workflow to trim entries and auto-collapse older dates (with localized <summary> labels).

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
README.md	Collapses older “What’s New” entries under a <details> section.
docs/README_CN.md	Same collapse behavior for Chinese README with localized <summary>.
docs/README_JA.md	Same collapse behavior for Japanese README with localized <summary>.
docs/README_FR.md	Same collapse behavior for French README with localized <summary>.
docs/README_DE.md	Same collapse behavior for German README with localized <summary>.
.github/workflows/readme-whats-new.yml	Automates trimming + collapsing older unique dates into <details> on each run.

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[Copilot]

result = "\n".join(visible) / "\n".join(collapsed) can cause the number of blank lines between entries to grow on every workflow run because each entry already contains trailing newlines (everything up to the next \n#### ...), and join adds an extra separator newline on top. This can bloat the README sections over time and already appears to be producing large vertical gaps. Consider normalizing entries before joining (e.g., strip leading/trailing newlines per entry) and then joining with a fixed separator (often "\n\n") so spacing stays stable run-to-run.

Suggested change

	result = "\n".join(visible)
	if collapsed:
	label = LANG_LABELS.get(readme_file, "Show earlier updates")
	result += "\n\n<details>\n<summary>" + label + "</summary>\n"
	result += "\n".join(collapsed)
	# Normalize entries to avoid accumulating blank lines across runs
	visible = [e.strip() for e in visible]
	collapsed = [e.strip() for e in collapsed]
	result = "\n\n".join(visible)
	if collapsed:
	label = LANG_LABELS.get(readme_file, "Show earlier updates")
	result += "\n\n<details>\n<summary>" + label + "</summary>\n\n"
	result += "\n\n".join(collapsed)