Fix project selection gating and expose max projects in resume UI

[DaKheera47]

I believe I worked out what the problem is. The problem is that when resumes were being imported, project IDs weren't assigned. And these project IDs are necessary for the AI to choose which projects to select. If these project IDs are empty, the AI selects nothing and it shows as empty.

Summary

• Revalidate saved project selections during job tailoring so stale IDs no longer suppress automatic selection
• Add structured PROJECT_SELECTION_TRACE logging around the project-selection gate, candidate resolution, and saved output
• Show the max-projects control in the Reactive Resume and Projects panels, and clarify the tooltip copy
• Add regression coverage for stale selections and the new Projects-panel max-projects control

Testing

• Biome formatting and lint checks passed on the touched UI/server files
• Targeted Vitest coverage passed for project selection and Design Resume project controls
• Typecheck passed for the orchestrator workspace
• Client build passed