Add handoff kit product discovery and free worksheet

[azurras]

Summary

• Add a public Software Project Handoff Kit page with verified contents, usage permission, AI assistance disclosure, planned $15 USD price, and explicit purchase unavailability.
• Serve one fixed free Markdown worksheet as an attachment; keep the full paid toolkit/ZIP/PDF out of the website. Add public Tools discovery and canonical sitemap entry.
• Fix a verified build blocker: freeze the static asset fingerprint lazily on first read instead of rehashing the entire asset tree per YAML line. Preserve digest format and task inputs.

Verification

• New JS navigation regression failed before implementation; focused14/14 and full378/378 pass.
• Broad local Java XML:1978 total,137 skipped, one incorrect new test assumption failed. Existing unknown HTML GETs intentionally reach404. Corrected that expectation, added PUT/DELETE restrictions and neighbor404 tests; all70 affected Java tests pass. Passing unaffected evidence reused; full unfiltered platform CI remains the merge gate.
• Native counted-source/laziness and fingerprint-serialization gates, sensor-resolution gate and bootJar pass. Controlled asset change/restoration builds passed35s/13s and returned the original fingerprint; probe removed.
• Packaged native candidate18090 used only isolated Mongo27029/test with jobs/mail disabled. Anonymous page, sample byte/header response, sitemap and desktop/mobile discovery/layout passed. Candidate processes stopped; production remained running.
• Browser tool denied the download-button check after permission was declined. No workaround attempted; the earlier HTTP sample proof remains valid.
• Independent staged-patch review found no Critical/Important/Minor issues.

Evidence

Plan
Runtime report

Payment processing is deferred. No buyer data, spending, support commitment, database/schema change, or revenue claim.