docs: record Core v0.4.0 public proof

[jerelvelarde]

Outcome

Records the immutable public evidence for Core v0.4.0 after release publication.

• release PR chore(release): prepare Core v0.4.0 #23 and exact release commit
• post-main Linux/package, macOS, and Windows CI
• annotated tag object and exact peel
• GitHub release URL
• fresh depth-one public-tag checkout
• 32-file distribution, canonical digest vectors, and 13/13 conformance
• 48-file Core and 10-file CLI extracted-package proof
• fresh public Git-tag install at v0.4.0#71600176
• warning-free outside-checkout default init/validate
• clean detached source checkout

Environmental retry evidence is explicit: crates.io low-speed timeout and local disk pressure were resolved without changing the release inputs, then the unchanged proof passed offline. No crates.io publication, Cloud, sync, or hosted-byte claim is made.

Checks

• markdownlint: 0 errors
• all release evidence links: HTTP 200
• git diff --check
• public eclipse and CI-policy gates
• exact 32-file distribution
• both canonical Folderbase Version digests
• focused standards/spec self-review: no findings