chore: sync all pending changes — kirigami platform headers, cookbook fix, docs, patches

Kirigami: remove stub .cpp, add Qt platform integration headers for
QML gate. Matches KDE src/pattern for direct header-only builds.

Cookbook: add --no-backup-if-mismatch to patch invocation (fetch.rs).

Kernel: consolidate patch chain, add debug-scheme-serial-fix.

Docs: archive old audit reports, add CHANGELOG and hardware validation
matrix. Update AGENTS.md with Linux reference source policy.

Scripts: add test-network-qemu.sh, test-storage-qemu.sh.

.gitignore: add local/reference/ exclusion.

AGENTS.md

@@ -40,7 +40,8 @@ redox-master/
 │   ├── Assets/      # Branding assets (icon, loading background)
 │   ├── firmware/    # AMD GPU firmware blobs (fetched, not committed)
 │   ├── scripts/     # Build/deploy scripts (fetch-firmware.sh, build-redbear.sh)
-│   └── docs/        # Red Bear integration docs (AMD roadmap, Wi-Fi/Bluetooth plans, status notes)
+│   ├── docs/        # Red Bear integration docs (AMD roadmap, Wi-Fi/Bluetooth plans, status notes)
+│   └── reference/   # External reference sources (gitignored, never deleted, always kept)
 ├── prefix/          # Cross-compiler toolchain (Clang/LLVM for x86_64-unknown-redox)
 ├── build/           # Build outputs, logs, fstools, per-arch directories
 ├── repo/            # Package manifests and PKGAR artifacts per architecture
@@ -201,6 +202,22 @@ See `local/docs/BUILD-SYSTEM-HARDENING-PLAN.md` for the full plan.
 - **DO NOT** remove patches from `recipe.toml` to fix build failures — rebase the patch instead (see `local/docs/PATCH-GOVERNANCE.md`)
 - **DO NOT** remove BINS entries to fix build failures — fix the source or use EXISTING_BINS filtering
 
+## LINUX REFERENCE SOURCE POLICY
+
+`local/reference/linux-7.0/` (or later) contains a full Linux kernel source tree for
+cross-referencing driver behavior, hardware initialization sequences, register definitions,
+and error handling patterns.
+
+**Rules:**
+- **NEVER delete** the reference tree. It is gitignored but permanent.
+- **ALWAYS consult** the Linux source when building or fixing drivers, daemons, or any subsystem
+  that has a Linux counterpart (audio/HDA, GPU/DRM, networking, USB, PCI, ACPI, input, storage,
+  filesystems, scheduler, memory management).
+- **Update** the reference tree when a new stable Linux version is needed:
+  `git -C local/reference/linux-7.0 fetch --depth=1 origin tag:v7.x --force`
+- The reference tree is read-only for consultation purposes. No modifications.
+- Location: `local/reference/` is gitignored. It survives `make clean` and `make distclean`.
+
 ## DURABILITY POLICY
 
 Every change to an upstream-owned source tree (anything under `recipes/*/source/`) **must** be