feat(runtime): align platform runtime contexts

[magic-alt]

Summary

• Add BacktestRuntime, SandboxRuntime, and LiveRuntime contexts that boot shared kernel services.
• Align MetricCollector and Tracer with the V6 MetricsPort and TracerPort contracts.
• Add /api/v2/info exposing API version, contract_version, and runtime policy metadata.
• Update architecture/API docs and CHANGELOG.

PR 28/29/30 Checks

• Re-ran engines, adapters, and plugin SDK regression tests.
• No issues found requiring fixes.

Tests

python -m pytest tests/test_runtime_contexts.py tests/test_api_v2_observability.py \
  tests/engines/test_engines_layer.py tests/test_adapters_convergence.py \
  tests/test_plugin_spi_sdk.py -v
powershell -ExecutionPolicy Bypass -File scripts/local_ci.ps1 -Jobs test -SkipInstall

Result: 1274 passed, 35 skipped

[Copilot]

Pull request overview

This PR introduces V6 “runtime contexts” (Backtest/Sandbox/Live) as thin wrappers that boot a shared kernel service set, aligns the in-process observability utilities (MetricCollector, Tracer) to the V6 MetricsPort/TracerPort contracts, and adds a new /api/v2/info endpoint exposing contract/runtime metadata for operational introspection.

Changes:

• Added BacktestRuntime, SandboxRuntime, and LiveRuntime contexts that register runtime/metrics/tracer/plugin-registry into a PlatformKernel lifecycle.
• Updated MetricCollector and Tracer to satisfy MetricsPort and TracerPort (tagged metrics + context-managed spans with attributes).
• Added /api/v2/info plus corresponding docs and tests; updated CHANGELOG.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/test_runtime_contexts.py	Adds tests for runtime context policy metadata, kernel boot lifecycle, and port conformance.
tests/test_api_v2_observability.py	Extends API v2 tests to validate /api/v2/info and refactors span assertion formatting.
src/runtime/contexts.py	Implements the runtime context classes and lifecycle integration with PlatformKernel.
src/runtime/init.py	Exposes runtime context API at src.runtime.
src/platform/runtime.py	Adds platform-layer re-exports for runtime contexts.
src/platform/api_v2.py	Wires runtime contexts into the API app state and adds /api/v2/info.
src/core/monitoring.py	Updates tracer spans to be context managers with attributes; adds tagged metric helpers to match ports.
docs/architecture/open-platform.md	Documents Phase 6 runtime contexts and /api/v2/info.
docs/ARCHITECTURE_TARGET_STATE.md	Updates target-state architecture notes to include runtime contexts and /api/v2/info.
docs/api/rest-api.md	Adds /api/v2/info to the endpoint overview.
CHANGELOG.md	Records the new runtime contexts, observability alignment, /api/v2/info, and related tests.

Comments suppressed due to low confidence (1)

src/runtime/contexts.py:151

• _on_stop only records the stop counter when self.metrics is a concrete MetricCollector. If a custom MetricsPort is injected, runtime stop metrics will be silently skipped. Consider calling self.metrics.incr(...) directly to honor the port abstraction.

        self.state = RuntimeState.STOPPED
        if isinstance(self.metrics, MetricCollector):
            self.metrics.incr("runtime_stop_total", tags={"runtime": self.mode.value})

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.