Update documentation, enhance README, and version bump to 0.3.0

[FrozenLemonTee]

No description provided.

[Copilot]

Pull request overview

This PR focuses on a documentation overhaul (new bilingual user guide + API docs), updates project READMEs accordingly, refreshes a few examples to match the newer behaviors being documented, and bumps the project version to 0.3.0.

Changes:

• Bump project version to 0.3.0 in both xmake and CMake.
• Add structured documentation under docs/ (Guide + API, English + Chinese) and update root READMEs.
• Update examples to demonstrate mixed primitive/underlying operations and a more realistic fenced-concurrency workload.

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 15 comments.

Show a summary per file

File	Description
xmake.lua	Add project metadata (name/version) for xmake builds.
CMakeLists.txt	Bump CMake project version to 0.3.0.
examples/ex02_type_policy.cpp	Expand type-policy example to cover cross-underlying construction behavior.
examples/ex03_value_policy.cpp	Extend value-policy example to cover primitive/underlying mixed ops.
examples/ex05_concurrency_policy.cpp	Replace simple concurrency demo with mixed read/write workload + CAS check.
docs/guide/README.md	Add guide entry point.
docs/guide/en/*	New English guide pages (install, quick start, concurrency, extension).
docs/guide/zh/*	New Chinese guide pages (install, quick start, concurrency, extension).
docs/api/README.md	Add API docs entry point.
docs/api/en/README.md	New English API overview/reference.
docs/api/zh/README.md	New Chinese API overview/reference.
docs/README.md	Add docs root index linking Guide + API.
README.md	Refresh English README to match new docs and capabilities.
README.zh.md	Add Chinese README matching new docs and capabilities.
LICENSE	Fill in Apache 2.0 appendix boilerplate copyright line.
.github/prompts/plan-policyBehaviorProtocol.prompt.md	Remove an obsolete planning prompt document.