Implement Process Stabilization Grace Period (startsecs)

[alexmond]

Feature Request: Process Stabilization Period

Add startsecs configuration to define how long a process must stay running to be considered successfully started.

Requirements

• Add startsecs field to ProcessConfig (Duration, default: 1s)
• Track process startup time vs stabilization time
• Only consider process started after it runs for startsecs duration
• If process exits before startsecs, count as startup failure

Acceptance Criteria

• Process status shows starting until startsecs period passes
• Process status changes to running after stabilization period
• Early exits (before startsecs) are treated as startup failures