[hippi345]

Summary

Adds a contributed $lua problem matcher so shell tasks can parse Lua/LuaJIT stderr and surface errors in the Problems view (e.g. with "problemMatcher": ["$lua"] in tasks.json).

Changes

• Register contributes.problemMatchers named lua in package.json.
• Match common runtime error shapes: file:line: message, with an optional …/lua:, lua.exe: or luajit prefix, and fileLocation auto-detection.

Testing

• Built the client (npm ci, npm run build) after initializing submodules.
• Built the Addon Manager WebVue (client/webvue).
• Packaged with vsce package -t linux-x64.
• Spot-checked the regex against sample error lines. I haven't tried it end to end in VS Code yet.

Closes #134