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.

local/docs/HARDWARE-VALIDATION-MATRIX.md

@@ -0,0 +1,28 @@
+# Hardware Validation Matrix — Red Bear OS
+
+| Component | QEMU | Bare Metal | Notes |
+|-----------|------|------------|-------|
+| **Storage** | | | |
+| AHCI SATA | ✅ | 🔲 | NCQ structure present, not runtime-validated |
+| NVMe | 🔲 | 🔲 | Basic driver, no multiqueue |
+| virtio-blk | ✅ | N/A | QEMU only |
+| **Network** | | | |
+| e1000 | 🔲 | 🔲 | ITR structure present, no offload validation |
+| rtl8168 | 🔲 | 🔲 | PHY config present, not runtime-tested |
+| virtio-net | ✅ | N/A | QEMU only |
+| **Audio** | | | |
+| Intel HDA | 🔲 | 🔲 | Codec detection + jack sense added, not validated |
+| AC97 | 🔲 | 🔲 | Basic driver |
+| **Input** | | | |
+| PS/2 | ✅ | 🔲 | QEMU keyboard/mouse work |
+| USB HID | 🔲 | 🔲 | Hardened (P3), not validated on real HW |
+| **GPU/Display** | | | |
+| VESA | ✅ | 🔲 | QEMU framebuffer works |
+| virtio-gpu | ✅ | N/A | 2D only, QEMU |
+| **CPU/Power** | | | |
+| cpufreqd | 🔲 | 🔲 | Governors implemented, not HW-validated |
+| thermald | 🔲 | 🔲 | ACPI thermal zones, not HW-validated |
+| **SMP** | | | |
+| x2APIC/SMP | ✅ | ✅ | Multi-core works |
+
+✅ = validated  🔲 = implemented, not validated  N/A = not applicable