fix(agents): extend Rovo Dev startup timeout

[kunchenguid]

Summary

• Increase the Rovo Dev managed-process startup timeout so slower server launches do not fail prematurely.
• Add targeted Rovo Dev agent coverage for startup timeout handling, validated by npx vitest run src/core/agents/rovodev.test.ts.

Risk Assessment

✅ Low: The change is a narrowly scoped timeout increase for Rovo Dev server startup with no material correctness, security, performance, or simplification issues found in the changed code.

Testing

• Summary: Exercised the Rovo Dev agent startup, session, shutdown, abort, and new 90 second readiness-timeout boundary; the focused suite passes.
• npx vitest run src/core/agents/rovodev.test.ts
• Outcome: ✅ passed across 1 run (1m18s)

Pipeline

Updates from git push no-mistakes

✅ **Rebase** - passed

Round 1 - passed ✅

✅ **Review** - passed

Round 1 - passed ✅

✅ **Test** - passed

Round 1 - passed ✅

• npx vitest run src/core/agents/rovodev.test.ts

✅ **Document** - passed

Round 1 - passed ✅

✅ **Lint** - passed

Round 1 - passed ✅

✅ **Push** - passed

Round 1 - passed ✅