fix: restore libwayland redox.patch to working state, update docs

- Reverted redox.patch to original 39-line version (build-tested)
- Documented libwayland→qtbase→kded6 build dependency chain
- Updated WAYLAND-IMPLEMENTATION-PLAN.md to v2.1
- Deleted 45 stale .bak patch files
- pkgar restored from packages/ backup

local/docs/WAYLAND-IMPLEMENTATION-PLAN.md

@@ -1,5 +1,5 @@
 # Red Bear OS Wayland Implementation Plan
-**Version:** 2.0 (2026-05-06)
+**Version:** 2.1 (2026-05-06)
 **Status:** Canonical Wayland subsystem plan — **Wayland-only path, no framebuffer workarounds**
 
 ## Architecture Decision (2026-05-06)
@@ -154,3 +154,22 @@ Hardware DRM/KMS rendering depends on `redox-drm` driver maturity.
 
 Success criterion: `redbear-compositor: client 65536 connected` followed by
 `redbear-compositor: dispatch` (not a page fault).
+
+### Build Dependency Chain (Critical, discovered 2026-05-06)
+
+When modifying libwayland source or `local/patches/libwayland/redox.patch`, the
+full chain must be rebuilt:
+
+```
+libwayland recipe → repo/x86_64-unknown-redox/libwayland.pkgar
+qtbase recipe     → copies pkgar into sysroot → links Qt6 Wayland QPA
+kf6-kded6 recipe  → links against qtbase/sysroot/libwayland-client.a
+```
+
+**Failure mode**: Modifying only libwayland does NOT update qtbase's static copy
+of `libwayland-client.a`. The old binary persists in qtbase's sysroot. All
+three recipes must be force-rebuilt (delete `target/` directories) AND the
+repo pkgar cache must be regenerated.
+
+**Recovery**: If `repo/x86_64-unknown-redox/libwayland.pkgar` is deleted, a
+backup exists at `packages/x86_64-unknown-redox/libwayland.pkgar`.