[TASK][Timpani-n] Align task release times to hyperperiod boundaries

[LGSI-KarumuriHari]

📝 Task Description

Implement POSIX timer management for periodic activation timing aligned to hyperperiod.

📋 Checklist

• Calculate hyperperiod from task periods
• Align all task activations to hyperperiod start
• Use timer_create() with CLOCK_MONOTONIC
• Set timer for periodic activation
• Handle timer expiration via SIGALRM
• Minimize timer setup overhead

🔗 Related Requirement

Relates to #26 (Hyperperiod Management)
Relates to #17 (Implement Hyperperiod Management)

📐 Implementation Guidelines

• Functional Requirement: FR-8.2.1 - Align task release times to hyperperiod boundaries
• Component: timpani-n/Execution Layer/Timer Manager
• Calculate hyperperiod = LCM of all task periods
• Set timer to expire at hyperperiod boundaries
• Use absolute time (TIMER_ABSTIME) for precision
• Synchronize hyperperiod start across nodes

🧪 Testing Method

• Unit test: Verify hyperperiod calculation
• Timing test: Measure alignment accuracy
• Multi-node test: Verify synchronized hyperperiod start