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/BLUETOOTH-IMPLEMENTATION-PLAN.md

@@ -189,7 +189,7 @@ live under `local/`:
 - validation helpers under `local/scripts/`
 - support-language and roadmap updates under `local/docs/`
 
-That keeps the first implementation pass aligned with Red Bear's overlay model and rebase strategy.
+That keeps the first implementation pass aligned with Red Bear's release fork model and rebase strategy.
 
 ### 3. Desktop parity is not the first milestone
 
@@ -310,7 +310,7 @@ Some of the implementation targets below refer to upstream-managed trees such as
 
 In Red Bear, changes against those paths should be carried through the relevant patch carrier under
 `local/patches/` until intentionally upstreamed. This plan names the technical integration point,
-not a recommendation to edit upstream-managed trees outside Red Bear's normal overlay model.
+not a recommendation to edit upstream-managed trees outside Red Bear's normal release fork model.
 
 ### Phase B0 — Scope Freeze and Support Model