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/patches/base/P0-acpid-dmar-fix.patch

@@ -1,19 +0,0 @@
-diff --git a/drivers/acpid/src/acpi/dmar/mod.rs b/drivers/acpid/src/acpi/dmar/mod.rs
---- a/drivers/acpid/src/acpi/dmar/mod.rs
-+++ b/drivers/acpid/src/acpi/dmar/mod.rs
-@@ -475,8 +475,12 @@ impl<'sdt> Iterator for DmarRawIter<'sdt> {
-             .expect("expected a 2-byte slice to be convertible to [u8; 2]");
- 
--        let ty = u16::from_ne_bytes(type_bytes);
--        let len = u16::from_ne_bytes(len_bytes);
-+        let len = u16::from_ne_bytes(len_bytes) as usize;
-+
-+        if len < 4 {
-+            return None;
-+        }
-+
-+        let ty = u16::from_ne_bytes(type_bytes);
- 
--        let len = usize::try_from(len).expect("expected u16 to fit within usize");
- 
-         if len > remainder.len() {