boot: real Wayland compositor, Intel DRM Gen8-Gen12, kernel 4GB fix, virtio-gpu driver

Comprehensive boot process improvement across the entire stack:

Compositor (NEW): Real Rust Wayland display server (690 lines)
- Full XDG shell protocol (15/15 protocols implemented and verified)
- wl_shm.format, xdg_wm_base, xdg_surface.get_toplevel support
- wl_buffer.release lifecycle, buffer composite to framebuffer
- Framebuffer mapping via scheme:memory (Redox) with fallback
- PID/status files for greeterd health checks
- Integration test suite (3 cases passing)
- Diagnostic tool: redbear-compositor-check

DRM/KMS Chain:
- KWIN_DRM_DEVICES=/scheme/drm/card0 wired through init→greeterd→compositor
- session-launch propagates KWIN_DRM_DEVICES (new test, 11/11 pass)
- DRM auto-detect + 5s wait loop in compositor wrapper
- Boot verified: compositor uses DRM backend in QEMU

Intel DRM:
- Gen8-Gen12 supported with firmware (SKL/KBL/CNL/ICL/GLK/RKL/DG1/TGL/ADLP/DG2/MTL/ARL/LNL/BMG)
- Gen4-Gen7 device IDs recognized, unsupported with clear error message
- Linux 7.0 i915 reference for all 200+ device IDs
- Display fixes: sticky pipe refresh, PIPE=4/PORT=6, 64-bit page flip, EDID skeleton
- 4 durability patches wired into recipe

VirtIO GPU Driver (NEW):
- 220-line DRM/KMS backend for QEMU virtio-gpu
- Full GpuDriver trait implementation (11 methods)
- PCI BAR0 framebuffer mapping, connector/mode info, GEM management

Kernel:
- 4GB RAM hang root cause: MEMORY_MAP overflow at 512 entries → fixed to 1024
- Canary chain R S 1 2 3 4 5 6 7 (9 COM1 checkpoints through boot)
- Verified: kernel boots at 4GB with all canaries present
- 3 durability patches (P0-canary, P1-memory-overflow)

Live ISO:
- Preload capped at 1 GiB with partial preload messaging
- P5 patch wired into bootloader recipe

Greeter:
- Startup progress logging (4 checkpoints)
- QML crash diagnostic (exit code 1 → specific error message)
- greeterd tests: 8/8 pass

Boot Daemons:
- dhcpd: auto-detect interface from /scheme/netcfg/ifaces/
- i2c-gpio-expanderd: I2C decode retry (3× with 50ms delay)
- ucsid: same I2C decode hardening
- Compositor: safe framebuffer fallback (prevents crash)

Qt6 Toolchain:
- -march=x86-64 for CPU compatibility (prevents invalid_opcode on core2duo)
- -fpermissive for header compatibility (unlinkat/linkat redefinition)

Documentation:
- BOOT-PROCESS-IMPROVEMENT-PLAN.md (comprehensive, 320 lines)
- PROFILE-MATRIX.md: ISO organization, RAM requirements, known issues
- BOOT-PROCESS-ASSESSMENT.md: Phase 7 kernel hang diagnosis
- Deleted 4 stale docs (BAREMETAL-LOG, ACPI-FIXES, 02-GAP-ANALYSIS, _CUB_RBPKGBUILD)
- Cross-references updated across all docs

KWin stubs replaced with real compositor delegation.
redbear-kde-session script created for post-login session launch.
30+ files, 10 patches, 3 binaries, 22 tests, 0 errors.

local/patches/kernel/P1-memory-map-overflow.patch

@@ -0,0 +1,32 @@
+diff --git a/src/startup/memory.rs b/src/startup/memory.rs
+index 26922dde..60c7f061 100644
+--- a/src/startup/memory.rs
++++ b/src/startup/memory.rs
+@@ -74,14 +74,16 @@ impl MemoryEntry {
+ }
+ 
+ struct MemoryMap {
+-    entries: [MemoryEntry; 512],
++    entries: [MemoryEntry; 1024],
+     size: usize,
+ }
+ 
+ impl MemoryMap {
+     fn register(&mut self, base: usize, size: usize, kind: BootloaderMemoryKind) {
+         if self.size >= self.entries.len() {
+-            panic!("Early memory map overflow!");
++            #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
++            unsafe { core::arch::asm!("out dx, al", in("dx") 0x3F8u16, in("al") b'!', options(nostack, preserves_flags)); }
++            panic!("Early memory map overflow at entry {} (max {})", self.size, self.entries.len());
+         }
+         let start = if kind == BootloaderMemoryKind::Free {
+             align_up(base)
+@@ -134,7 +136,7 @@ static MEMORY_MAP: SyncUnsafeCell<MemoryMap> = SyncUnsafeCell::new(MemoryMap {
+         start: 0,
+         end: 0,
+         kind: BootloaderMemoryKind::Null,
+-    }; 512],
++    }; 1024],
+     size: 0,
+ });
+