Improve search performance, remove dead sites, add sorting options

[niclimcy]

Summary

• Improve search performance by fetching postId concurrently
• Remove dead sites (DarkScans, MangaClash, ManhuaFast, PlatinumScans)
• Remove TheBlank, AzoraMoon as it no longer uses madara theme
• Add sorting options
• Update to new search API

Checklist

Making changes

• Follows Inkdex's Contributing Guidelines.

For updates to existing extensions

• Updated pbConfig.version for extension specific changes or BASE_VERSION for generic wide changes.

For new extensions

• Generated tests with npx paperback-cli test --generate EXTENSION_NAME.

Testing changes

• npm run conformance passes.
• npm test -- EXTENSION_NAME passes.
• Bundled the extension and verified it works in the Paperback app.

Committing changes

• Commit messages follow the existing convention (type(Scope): summary, e.g. fix(EXTENSION_NAME): ...).

AI assistance

Pick one:

• This PR contains no AI-assisted changes.
• This PR is AI-assisted. I manually reviewed every change and added an Assisted-by: AGENT_NAME:MODEL_VERSION trailer to each AI-assisted commit.