Add Builder.from() copy constructor to MantisJobClusterMetadataView

[hellolittlej]

Context

• Adds a static Builder.from(MantisJobClusterMetadataView) factory method to MantisJobClusterMetadataView.Builder that copies all fields from an existing instance
• Enables creating modified copies of an immutable MantisJobClusterMetadataView without repeating all field assignments

WHY
MantisJobClusterMetadataView is fully immutable with no setters. When overlaying a field (e.g. jobPrincipal from a global store) onto an existing instance returned from Akka, callers previously had to manually copy all constructor arguments. The from() factory method eliminates this boilerplate and makes the pattern future-proof if new fields are added to the class.

Checklist

• ./gradlew build compiles code correctly
• Added new tests where applicable
• ./gradlew test passes all tests
• Extended README or added javadocs where applicable

[github-actions]

Test Results

164 files  ±0  164 suites  ±0   10m 15s ⏱️ -55s
795 tests ±0  784 ✅ +1  11 💤 ±0  0 ❌  - 1 
795 runs   - 1  784 ✅ ±0  11 💤 ±0  0 ❌  - 1 

Results for commit fbbe49f. ± Comparison against base commit 254c035.

♻️ This comment has been updated with latest results.