Drop joeyblog branding from kernel build artifact names

Rename the kernel LOCALVERSION used by the build from
-joeyblog-bbrv3 / -joeyblog-bbrv3-max to -bbrv3 / -bbrv3-max, so the
produced uname strings and .deb package names no longer carry the
custom brand. Standard vs max kernels stay distinguishable.

- .github/workflows/build.yml: matrix localversion for all four jobs
- scripts/build-bbrv3-max-kernel.sh: LOCALVERSION for local max builds
- install.sh: update detection, profile matching, expected-uname and
  uninstall logic to key off -bbrv3 / -bbrv3-max instead of joeyblog
- README.md: describe uninstall by the new package-name suffixes

Runtime config paths (e.g. /etc/sysctl.d/99-joeyblog.conf) and author
attribution are unchanged; they are not kernel names.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PvXBX9hm6GzStHUMDZzDoZ

.github/workflows/build.yml

@@ -95,25 +95,25 @@ jobs:
             profile: standard
             profile_name: BBRv3
             release_suffix: ""
-            localversion: -joeyblog-bbrv3
+            localversion: -bbrv3
           - arch: arm64
             runs_on: ubuntu-24.04-arm
             profile: standard
             profile_name: BBRv3
             release_suffix: ""
-            localversion: -joeyblog-bbrv3
+            localversion: -bbrv3
           - arch: x86_64
             runs_on: ubuntu-latest
             profile: max
             profile_name: BBRv3 Max
             release_suffix: -max
-            localversion: -joeyblog-bbrv3-max
+            localversion: -bbrv3-max
           - arch: arm64
             runs_on: ubuntu-24.04-arm
             profile: max
             profile_name: BBRv3 Max
             release_suffix: -max
-            localversion: -joeyblog-bbrv3-max
+            localversion: -bbrv3-max
     runs-on: ${{ matrix.runs_on }}
     env:
       ARCH: ${{ matrix.arch }}