feat: build system transition to release fork + archive hardening

Release fork infrastructure:
- REDBEAR_RELEASE=0.1.1 with offline enforcement (fetch/distclean/unfetch blocked)
- 195 BLAKE3-verified source archives in standard format
- Atomic provisioning via provision-release.sh (staging + .complete sentry)
- 5-phase improvement plan: restore format auto-detection, source tree
  validation (validate-source-trees.py), archive-map.json, REPO_BINARY fallback

Archive normalization:
- Removed 87 duplicate/unversioned archives from shared pool
- Regenerated all archives in consistent format with source/ + recipe.toml
- BLAKE3SUMS and manifest.json generated from stable tarball set

Patch management:
- verify-patches.sh: pre-sync dry-run report (OK/REVERSED/CONFLICT)
- 121 upstream-absorbed patches moved to absorbed/ directories
- 43 active patches verified clean against rebased sources
- Stress test: base updated to upstream HEAD, relibc reset and patched

Compilation fixes:
- relibc: Vec imports in redox-rt (proc.rs, lib.rs, sys.rs)
- relibc: unsafe from_raw_parts in mod.rs (2024 edition)
- fetch.rs: rev comparison handles short/full hash prefixes
- kibi recipe: corrected rev mismatch

New scripts: restore-sources.sh, provision-release.sh, verify-sources-archived.sh,
check-upstream-releases.sh, validate-source-trees.py, verify-patches.sh,
repair-archive-format.sh, generate-manifest.py

Documentation: AGENTS.md, README.md, local/AGENTS.md updated for release fork model

local/docs/repo-governance.md

@@ -53,9 +53,9 @@ why it is intentionally excluded.
 - Red Bear builds must remain resilient when access to upstream Redox infrastructure is degraded or
   unavailable.
 - Local package/source copies are the default operational source of truth for builds.
-- Upstream fetch/refresh is opt-in and must be explicitly requested by the operator (for example via
+- Upstream fetch/immutable archived is opt-in and must be explicitly requested by the operator (for example via
   an explicit `--upstream` workflow).
-- After an explicit upstream refresh, local durable overlays (`local/patches`, `local/recipes`) stay
+- After an explicit upstream immutable archived, local durable release fork (`local/patches`, `local/recipes`) stay
   authoritative until a conscious reevaluation/promotion decision is made.
 
 ## Profile Intent
@@ -94,6 +94,6 @@ For any substantial Red Bear change, record:
 
 ## Upstream Sync Discipline
 
-- Rebase/sync through `local/scripts/sync-upstream.sh`.
+- Rebase/sync through `local/scripts/provision-release.sh`.
 - Keep Red Bear-specific diffs easy to audit.
 - Update profile docs when config inheritance or package composition changes.