Remove `Joakker/lua-json5` — narrow use case already covered by existing plenary JSONC helper

[ooloth]

Current state

lua-json5 is declared as a plugin dependency in nvim-dap.lua to handle trailing commas when parsing launch.json. The spec file already imports and uses plenary's json_strip_comments for JSONC handling at line 168. lua-json5 adds an external build = './install.sh' compilation step at install time and introduces a dependency on a 46-star repository with 29 total commits and no documented maintainer activity — for a use case that the existing plenary path already addresses.

Ideal state

• nvim-dap.lua does not declare a dependency on Joakker/lua-json5
• launch.json files continue to be parsed using the existing plenary-based JSONC path in the spec
• No build = './install.sh' step runs when installing or updating DAP plugins

Out of scope

Any trailing-comma edge cases that the plenary JSONC helper cannot handle — if such cases exist, they should be documented in a separate issue.

Starting points

• lua/config/plugins/specs/nvim-dap.lua — line 84 declares { 'Joakker/lua-json5', build = './install.sh' } as a dependency; line 168 shows the existing plenary-based JSONC parsing path

QA plan

1. Remove { 'Joakker/lua-json5', build = './install.sh' } from the dependencies list in nvim-dap.lua
2. Run nvim --headless -c "qall" — expect no startup errors
3. Trigger a lazy.nvim sync (:Lazy sync) — expect no lua-json5 installation or build step
4. Open a project that has a launch.json and trigger DAP config loading — expect no parse errors

Done when

nvim-dap.lua no longer lists Joakker/lua-json5 as a dependency and DAP config loading continues to parse launch.json without errors.