Sentinel v0.11.0

Sentinel 0.11.0

A packaging-only release — no changes to runtime behaviour, configuration,
or the PAM/polkit auth path. It fixes the AUR build and stops the KDE
package from compiling the COSMIC GUI stack it never uses.

Fixes

• AUR build was broken — the KDE package() installed config/su, a
  PAM reference doc that was never committed, so sentinel-kde 0.10.0
  failed in package() for everyone. The file is now shipped (it mirrors
  config/sudo).

• KDE package compiled the entire COSMIC/libcosmic stack — both
  PKGBUILDs selected crates with --workspace --exclude <other-helper>,
  and the KDE check() combined --workspace with -p, where
  --workspace overrode the -p filter and pulled the whole workspace
  (including the libcosmic frontend) into the test build. build() now
  uses explicit per-frontend -p target lists, so each package compiles
  only its own frontend plus the shared backend.

• Removed the in-package test step — check() is gone from both
  PKGBUILDs. cargo fmt/clippy/test already run in CI on every push
  and the AUR publish is gated on a green release, so re-running the test
  suite on every user's machine was redundant build time.