fix: eliminate CI/CD duplication for cherry-pick commits

- CI/CD build now skips cherry-pick commits on maintenance branches
- maintenance-fast.yml provides targeted validation for cherry-picks
- Eliminates redundant full builds while preserving coverage for direct pushes
- Cherry-picks: fast targeted build only (43s)
- Direct pushes: full CI/CD validation as needed

Author: markpollack

.github/workflows/continuous-integration.yml

@@ -14,7 +14,7 @@ jobs:
   build:
     name: Build branch
     runs-on: ubuntu-latest
-    if: ${{ github.repository_owner == 'spring-projects' }}
+    if: ${{ github.repository_owner == 'spring-projects' && !contains(github.event.head_commit.message, '(cherry picked from commit') }}
     services:
       ollama:
         image: ollama/ollama:latest