Feat/event driven simulation

[Rionlyu]

Summary

Adds deterministic, event-driven workload simulation to TopoQueue through a new simulate command:

topoqueue simulate \
  --cluster examples/cluster.yaml \
  --jobs examples/timed-jobs.yaml \
  --policy all \
  --output text

TopoQueue can now model job arrivals, queue waiting, topology-aware admission, fixed-duration execution, completion, exact resource release, and retries at subsequent scheduling events.

## What changed

- Added a separate strict timed-workload YAML model and loader.
- Implemented a logical-tick event loop with deterministic ordering:
    1. completions;
    2. arrivals;
    3. admissions.

- Added exact, checked resource reclamation using recorded allocations.
- Implemented strict FIFO and backfill behavior over time.
- Added terminal handling for permanently unschedulable jobs.
- Added lifecycle results, event timelines, and queue-delay metrics.
- Added concurrent, isolated comparison of both timed policies.
- Added stable text and JSON simulation output.
- Added make demo-simulate, a deterministic benchmark, documentation, and lifecycle-focused test coverage.

## Example results

 Policy         Completed    Makespan    Total wait    Average wait    Maximum wait
━━━━━━━━━━━━━  ━━━━━━━━━━━  ━━━━━━━━━━  ━━━━━━━━━━━━  ━━━━━━━━━━━━━━  ━━━━━━━━━━━━━━
 Backfill               3          12             7            2.33               7
─────────────  ───────────  ──────────  ────────────  ──────────────  ──────────────
 Strict FIFO            3          14            17            5.67              10

Backfill reduces queue delay and makespan by using otherwise idle capacity while the larger queue-head job waits for the full cluster.

## Compatibility

- Existing schedule and compare behavior remains unchanged.
- Timed workloads use a separate loader, so existing static input validation and JSON shapes remain stable.
- Simulations use logical integer ticks only—no sleeps, wall-clock time, randomness, or background timers.
- This remains an educational scheduling simulator and does not claim Kubernetes, Kueue, or production-scheduler compatibility.

## Validation

- [x] make fmt-check
- [x] make vet
- [x] make test
- [x] make build
- [x] make demo
- [x] make demo-simulate
- [x] make benchmark
- [x] 20 consecutive package test runs
- [x] Byte-identical text and JSON across three independent renders
- [x] Independent branch review completed with no remaining actionable findings