feat: merge develop into master

[MikiEEE]

Summary

This brings the accumulated develop work into master.

• Adds runtime failure handling so uncaught task exceptions, cancellations, and invalid I/O failures can be surfaced through a configurable handler without crashing the scheduler.
• Cleans up task wait/cancellation bookkeeping, including join and signal waiters, to prevent stale registrations and duplicate resumes.
• Adds file-descriptor validation and moves task-block orchestration into the runtime/OS boundary.
• Adds persistent I/O readiness registration: Unix reuses a selector, MicroPython reuses its polling backend when available, and the previous snapshot wait path remains as a compatibility fallback. Includes kernel/runtime regression coverage and an I/O-wait benchmark.
• Introduces the first two typing layers: shared type definitions, annotations across the core runtime/configuration/kernel utilities, py.typed, and Pyright configuration, including an explicit type-only contract for dynamic poll event results.
• Adds dependency-free execution adapters: a bounded thread bridge for blocking libraries and a persistent asyncio-loop bridge, with common completion handling, lifecycle/error contracts, adapter tests, and SQLite/asyncio demos.
• Adds CI gates for static typing, CPython 3.10-3.13 tests, branch coverage, and built-wheel installation/smoke verification.
• Automates GitHub Releases after successful master CI: Conventional Commit PR validation, semantic version tags at the tested SHA, rebuilt/verified wheel and sdist assets, idempotent reruns, and an existing-tag asset repair path. PyPI publishing remains disabled pending distribution-name ownership.
• Updates package metadata, build configuration, README guidance, demos, and core list/task utilities to support the above.

Scope

Relative to master, this PR changes 41 files: 5,924 additions and 326 deletions.

Merge note

The release workflow now exists on develop. Once this PR merges successfully into master and Python CI passes, it is designed to create the corresponding immutable tag and GitHub Release.