v0.6.0 — Deadline-Aware Scheduling

OpenStreamGrid 0.6.0 completes a three-phase scheduling program that makes
delivery decisions reproducible, extensible, and aware of playback deadlines.
The release adds a controlled QoE benchmark foundation, extracts Node and
browser scheduling behind shared contracts, and introduces deadline-aware
Origin hedging while preserving verified Origin fallback as the final safety
boundary.

Phase 1 — Reproducible Benchmarking and QoE Measurement

• Added versioned benchmark scenarios, deterministic seeded execution, JSON
  schema validation, and environment provenance for repeatable experiments.
• Expanded measurement to include request outcomes, deadline misses, stall
  proxies, latency percentiles, P2P efficiency, Origin fallback, and Jain's
  fairness index.
• Added repeated-run aggregation with confidence intervals, result comparison
  with drift warnings, self-contained SVG reports, CI execution, and a documented
  benchmark methodology.

Phase 2 — Pluggable Scheduling Core

• Added shared SegmentScheduler contracts, scheduling plans, observations,
  decision records, and exception-safe plan validation.
• Extracted the existing Node weighted-score policy and browser trust/latency
  probe policy into injectable schedulers without changing their default
  selection behavior.
• Added batch planning, decision replay, characterization coverage, structured
  scheduler warnings, and lifecycle hooks while keeping malformed or failing
  custom policies behind an immediate Origin fallback.

Phase 3 — Deadline-Aware Scheduling and Hedged Origin Requests

• Added deadline-aware scheduler decorators for Node peers and the browser SDK.
  Unknown deadlines retain legacy P2P-first behavior, relaxed deadlines allow
  peer attempts, and critical deadlines select Origin immediately.
• Derived synthetic Node deadlines and Hls.js playback deadlines, and added a
  bounded Origin-latency estimator for deciding the latest safe fallback start.
• Added first-success-wins hedged P2P/Origin execution with cancellation,
  request coalescing, abort propagation, and explicit scheduler statistics.
• Added a deterministic scheduler lab with critical, tight, relaxed,
  slow-Origin, unreliable-peer, and mixed-workload scenarios. The committed
  mixed-workload simulation reaches a 100% deadline-met rate for both
  deadline-aware policies; this is a controlled scheduler result, not a
  production capacity claim.

Validation

• npm run build
• npm run typecheck
• npm test (226 tests)
• npm run lint

The release-preparation fix also excludes nested workspace dist-test
artifacts through ESLint's flat configuration, preventing generated test output
from being linted in CI.