feat: add Debian Trixie (testing) to CI test matrix

Add forward compatibility testing with Debian 13 "Trixie" (testing release).

Changes:
- Add debian:trixie to installer-test matrix
- Set continue-on-error for Trixie (testing can be unstable)
- Add fail-fast: false to run all OS tests even if one fails
- Update comments to clarify Debian/Ubuntu versions

Benefits:
- Early detection of BlueZ/DBus API changes
- Test compatibility with newer system packages
- Forward compatibility assurance before Trixie stable release
- Non-blocking (Trixie failures won't block merges)

Matrix now tests:
- Debian 12 (Bookworm - current stable)
- Debian Trixie (testing - next release) [NEW]
- Ubuntu 22.04 LTS (Jammy)
- Ubuntu 24.04 LTS (Noble)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/test.yml

@@ -123,12 +123,17 @@ jobs:
     runs-on: ubuntu-latest
 
     strategy:
+      fail-fast: false
       matrix:
         os-image:
-          - "debian:12"      # Debian Bookworm (latest stable)
-          - "ubuntu:22.04"   # Ubuntu Jammy
+          - "debian:12"      # Debian Bookworm (current stable)
+          - "debian:trixie"  # Debian Trixie (testing - next release)
+          - "ubuntu:22.04"   # Ubuntu Jammy LTS
           - "ubuntu:24.04"   # Ubuntu Noble (latest LTS)
 
+    # Allow Trixie to fail without blocking CI (testing can be unstable)
+    continue-on-error: ${{ matrix.os-image == 'debian:trixie' }}
+
     container:
       image: ${{ matrix.os-image }}
       env: