feat: bilingual docs, GitHub Pages deployment, and concurrency bug fixes

[jrfk]

Summary

Completes the library for public consumption: comprehensive bilingual documentation deployed to GitHub Pages, plus fixes for eight real concurrency bugs found during review — each verified by a repro and covered by regression tests (suite grows 69 → 92 tests).

Documentation (English / 日本語)

• MkDocs Material + mkdocs-static-i18n + mkdocstrings, covering the full public API:
  • Guides: waiting for values, iterating over changes, deriving & composing, tasks & cancellation, events/streams/timing — all fully bilingual (*.md / *.ja.md).
  • API reference generated from docstrings (added docstrings + type annotations to all AsyncValue methods).
• GitHub Pages deployment workflow (docs.yml); Pages is already enabled with the 'GitHub Actions' source → deploys on merge to https://jrfk.github.io/asyncio-util/ (ja: /ja/).
• Bilingual READMEs, CHANGELOG.md, runnable examples/, strict docs build in CI.

Bug fixes (all with regression tests)

Bug	Symptom
wait_value(held_for=)	raised TimeoutError when the condition successfully held
eventual_values(held_for=)	hold logic inverted + unhandled TimeoutError to the consumer
raising predicates	crashed the assigning task and starved every later waiter; now delivered to their own waiter only
compose_values()	_transform_ exceptions silently swallowed → output frozen at last good value
move_on_when()	leaked CancelledError (body never ran) when the trigger completed without awaiting, e.g. an already-set event; trigger exceptions were swallowed
run_and_cancelling() / start_and_cancelling()	background failure masked the body's own exception
wait_any() / wait_all() / wait_any_map()	leaked already-started tasks when a later callable raised synchronously
MulticastQueue	broadcasting a legitimate None terminated listeners (sentinel collision)
periodic()	cumulative drift; now anchored to the absolute start + k*period grid

Housekeeping

• requires-python >= 3.10 (3.8/3.9 are EOL); CI matrix 3.10–3.14 + docs build job.
• py.typed, project metadata (description, keywords, classifiers, Pages URL), pytest asyncio_mode=auto, version 0.1.0.

Test plan

• uv run pytest — 92 tests pass (69 existing + 23 new regression tests)
• uv run mkdocs build --strict — clean, en + ja both built
• All three examples/*.py run with expected output
• uv build — wheel includes py.typed
• After merge: docs workflow deploys to https://jrfk.github.io/asyncio-util/