Add initial bsp/web scaffold for the experimental Emscripten target

[Copilot]

This PR fills in the missing bsp/web BSP entrypoint so the repository has a dedicated Web target instead of only scattered Emscripten-related compatibility code under bsp/pc. The new scaffold establishes the Web BSP boundary and keeps unsupported browser-specific behavior intentionally minimal.

• What this adds

  • Introduces a new bsp/web/ directory with the initial build/runtime scaffold
  • Defines a Web-specific BSP config via LUAT_BSP_WEB
  • Adds a minimal Web entrypoint and network stub to avoid inheriting PC POSIX socket initialization by accident

• BSP structure

  • bsp/web/include/luat_conf_bsp.h
    • Adds the Web BSP identity and a minimal feature set focused on VM/VFS/runtime basics
  • bsp/web/src/main_mini.c
    • Creates a Web-specific startup path
    • Reuses the existing shared runtime pieces from bsp/pc
    • Wraps reused log init/deinit behind Web-named helpers
  • bsp/web/port/network/luat_network_adapter_web.c
    • Provides a no-op luat_network_init() placeholder for browser builds

• Build entry

  • bsp/web/xmake.lua
    • Adds an initial xmake target for the Web BSP
    • Reuses the smallest viable subset of bsp/pc support code and core modules needed to boot the runtime

• Docs

  • bsp/README.md
    • Registers web/ as a BSP target
  • bsp/web/README.md
    • Documents current scope and intended Emscripten usage

Example of the new Web-specific boundary:

#define LUAT_BSP_WEB 1

void luat_network_init(void) {
}

Original prompt

完成bsp/web

Created from Copilot CLI via the copilot delegate command.

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[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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