Fix Windows Rust CI cache: full target, Cargo registry, explicit save.

Cache the entire windows-setup target tree plus ~/.cargo; split restore/save; skip cargo build when all release binaries are present.

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/actions/cache-windows-rust-tools/action.yml

@@ -1,18 +1,21 @@
-name: Cache Windows installer Rust binaries
-description: Restore or save compiled windows-setup release executables
+name: Restore Windows Rust build cache
+description: Restore Cargo registry, git checkouts, and the windows-setup target directory
 
 outputs:
   cache-hit:
-    description: Whether Rust installer tools were restored from cache
+    description: Whether an exact cache key match was restored
     value: ${{ steps.cache.outputs.cache-hit }}
 
 runs:
   using: composite
   steps:
-    - uses: actions/cache@v5
+    - uses: actions/cache/restore@v5
       id: cache
       with:
-        path: app/desktop/windows-setup/target/release
-        key: windows-rust-tools-v1-${{ hashFiles('app/desktop/windows-setup/Cargo.lock') }}
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+          app/desktop/windows-setup/target
+        key: windows-rust-${{ runner.os }}-v2-${{ hashFiles('app/desktop/windows-setup/Cargo.lock', 'app/desktop/windows-setup/Cargo.toml', 'app/desktop/windows-setup/**/src/**', 'app/desktop/windows-setup/**/build.rs') }}
         restore-keys: |
-          windows-rust-tools-v1-
+          windows-rust-${{ runner.os }}-v2-