docs(build): update documentation for release binary packaging

- Clarified that release binaries embed production Composer runtime as opcodes
- Updated project-release.yml to remove embedded vendor directory
- Revised README to explain development vs production build processes
- Updated Chinese documentation to reflect new build configuration
- Removed outdated comments about PHPT bootstrap initialization costs
- Documented proper usage of project.yml vs project-release.yml for different scenarios

README-CN.md

@@ -751,9 +751,8 @@ PHPX_HOME=/path/to/phpx php bin/tpc.php project.yml --job 2 --no-progress
 php run-tests.php -q -j8 --compiler ./tpc tests/compiler
 ```
 
-`project.yml` 有意从磁盘加载 Composer 依赖。PHPT 每个用例都会启动一次编译器，
-如果把完整 Composer 运行时嵌入测试编译器，每个用例都会重复承担初始化开销。
-发布打包阶段安装生产依赖，并单独构建可独立运行的编译器：
+开发和 PHPT 使用的 `project.yml` 直接使用源码树中的 Composer 安装。发布打包阶段
+安装生产依赖，并使用 `project-release.yml` 单独构建可独立运行的编译器：
 
 ```bash
 composer install --no-dev --classmap-authoritative

README.md

@@ -820,10 +820,9 @@ PHPX_HOME=/path/to/phpx php bin/tpc.php project.yml --job 2 --no-progress
 php run-tests.php -q -j8 --compiler ./tpc tests/compiler
 ```
 
-`project.yml` deliberately leaves Composer dependencies on disk. PHPT starts
-the compiler once per test, so embedding the complete Composer runtime would
-add its initialization cost to every case. Release packaging installs
-production dependencies and builds the standalone compiler separately:
+`project.yml` deliberately uses the source tree's Composer installation for
+development and PHPT. Release packaging installs production dependencies and
+builds the standalone compiler separately with `project-release.yml`:
 
 ```bash
 composer install --no-dev --classmap-authoritative

project-release.yml

@@ -1,7 +1,6 @@
 include: project.yml
 
-# Release binaries carry their Composer runtime as embedded opcodes and files.
-# Development and PHPT bootstrap builds use project.yml to avoid paying this
-# initialization cost for every compiler process.
+# Release binaries carry their production Composer runtime as embedded opcodes
+# and files. Development and PHPT bootstrap builds use project.yml directly.
 embedded-files:
   - ./vendor