feat: recipe durability guard — prevents build system from deleting local recipes

Add guard-recipes.sh with four modes:
- --verify: check all local/recipes have correct symlinks into recipes/
- --fix: repair broken symlinks (run before builds)
- --save-all: snapshot all recipe.toml into local/recipes/
- --restore: recreate all symlinks from local/recipes/ (run after sync-upstream)

Wired into apply-patches.sh (post-patch) and sync-upstream.sh (post-sync).
This prevents the build system from deleting recipe files during
cargo cook, make distclean, or upstream source refresh.

local/recipes/drivers/redox-driver-pci/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "redox-driver-pci"
+version = "0.1.0"
+edition = "2024"
+description = "PCI bus backend for redox-driver-core"
+
+[dependencies]
+redox-driver-core = { path = "../redox-driver-core" }
+redox_syscall = "0.7"