bit `Bswup` improvements

[msynk]

bit Bswup improvements:

• Logging is half-implemented (advertised but dead)
• Version drift between Bswup runtime and Blazor's framework hashes
• Atomicity - the install can leave a torn cache
• handleInstall doesn't actually wait
• handleActivate still uses the old cache
• URL matching is brittle
• Race in reload() for first install
• Default Blazor script path mismatch with old templates
• handleControllerChange is dead code
• Multi-tab story is missing
• No update polling
• assetsManifest.version is the only "version" - fragile
• PROHIBITED_URLS returns Response with status 405 via respondWith
• prepareRegExpArray silently drops non-RegExp entries
• forceRefresh deletes only its own caches but leaves Blazor's
• BswupProgress.razor uses to bootstrap
• Static event handlers on the global page
• BswupMessage.updateInstalled is declared but never used
• enableCacheControl only sets request-side options
• disableHashlessAssetsUpdate semantics
• caseInsensitiveUrl only applies to handleFetch matching
• No retry / backoff for failed asset downloads
• Cleanup SW posts 'WAITING_SKIPPED' to clients that are listening for UNREGISTER
• precachedAssetsInclude is referenced in demo but not in code
• CSS bug in BswupProgress.razor for ShowAssets
• README and code version mismatch + drift
• Single global BitBswup namespace and side-effects at module load