Keep YouTube fallback statistics and styling consistent

[variablenix]

Summary

• Enrich successful API, public-page, and indexed YouTube searches with one shared best-effort public statistics lookup.
• Preserve the existing yellow eye/views and green thumbs-up/likes styling on fallback results, including age-confirmation search pages.
• Limit enrichment to one second within the command deadline; missing, malformed, unavailable, or quota-limited counts never discard a working title/link.
• Preserve base emojis without invisible variation selectors, IRC byte limits, and optional-key behavior.
• Update plugin documentation and add synthetic regression coverage for all routes, missing counts, genuine zero counts, quotas, timeouts, and skipped API requests.

Validation

• Full repository race tests, go vet, Staticcheck, govulncheck, and production build: passed.
• Live checks on the deployment host: a restricted-result search and a regular-video search both returned public view and like counts using the configured API key.
• Required GitHub Verify, Analyze Go, and CodeQL checks: passed, including the post-merge workflows.

Statistics remain provider-dependent. Unavailable counts are omitted, not invented. This change does not bypass playback age/sign-in restrictions.

Deployment

Merged revision rebuilt and deployed; GoBot restarted successfully. The running binary revision was verified, configuration and environment were preserved, both configured IRC networks reconnected, and metrics were reachable. Three live queries repeated three times all returned public view and like counts. Temporary test/deployment files were cleaned up.