Two symmetric changes so a site published as flat .html files (sirius.x
has tld.html, portal.html, market.html, register.html, studio.html)
reads with clean URLs to the visitor.
1. S3 handler fallback order for extensionless requests:
/tld → tld.html (new — first)
/tld → tld/index.html (existing — second)
/... → index.html (existing — SPA last-resort)
Requests with a real file extension (.js, .svg, .json) are never
rescued — those must never be routed by a client-side router and
swallowing them would hide real bugs.
2. transformHtml() gains stripHtmlExt(): rewrites href="foo.html"
(relative) to href="foo", preserving anchor and query. Absolute
URLs (https://silentmode.st/tlds/) are left alone — external
references are none of our business.
Backwards-compatible: existing /bns/<name>/foo.html links still 200.
Verified end-to-end on sirius.x: /tld, /portal, /market, /register,
/studio all serve; assets under js/, assets/ unchanged; direct .html
requests still work.
e130596584