review: address 2 Copilot review comments

- Add homepage.workspace to root package (missing vs subcrates)
- Gate Docker test-docker job to push only (seccomp:unconfined
  and SYS_ADMIN are unsafe for untrusted PR contexts)

.github/workflows/ci.yml

@@ -61,6 +61,7 @@ jobs:
 
   test-docker:
     name: Test (${{ matrix.target }})
+    if: github.event_name == 'push'
     runs-on: ubuntu-latest
     strategy:
       matrix:

Cargo.toml

@@ -8,6 +8,7 @@ rust-version.workspace = true
 license.workspace = true
 authors.workspace = true
 repository.workspace = true
+homepage.workspace = true
 description = "Memory-safe Rust reimplementation of Linux shadow-utils"
 readme = "README.md"
 keywords = ["shadow-utils", "uutils", "shadow", "passwd", "linux"]