Fix SSH workspace origin remote forwarding

[ammar-agent]

Fixes the SSH create workspace flow to properly forward the origin remote instead of leaving it pointing to the temporary bundle file.

Changes

Implementation

• Forward actual origin URL: After cloning from bundle on remote, set origin to the actual repository URL
• Remove bundle origin: If no origin exists locally, remove the bundle-pointing origin to avoid confusion
• Refactored code: Use execAsync utility instead of manual spawn pattern (no code duplication)
• Better logging: Errors go to init log (user-visible) instead of debug log

Testing

• Added targeted SSH-specific test outside matrix tests
• Test verifies origin remote points to actual repository URL, not bundle path
• Exported streamToString for test reuse (no duplication)

Behavior

• Non-fatal: If setting origin fails, logs warning but continues (won't break workspace creation)
• Filters bundle paths: Prevents propagation of temporary bundle URLs
• Gracefully handles missing origin remotes

Follows TDD approach with test written first.