test(config): verify Vim/Neovim config payload parity

Expose the init_options payload builders publicly in both clients
(M.init_options/M.server_settings in Lua, nuwiki#lsp#settings() in Vim) so
they can be inspected. Add editor harnesses that dump each client's
server-bound config as deterministic key=value lines and diff against a
shared golden file: nvim == golden and vim == golden together prove the two
clients send identical config. Add a server-side test asserting the Vim flat
shape and the Neovim {nuwiki:{...}} wrapper desugar to the same WikiConfig.
Wire both harnesses into CI.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -96,3 +96,7 @@ jobs:
         run: ./development/tests/test-keymaps.sh
       - name: run Vim keymap harness
         run: ./development/tests/test-keymaps-vim.sh
+      - name: run Neovim config parity harness
+        run: ./development/tests/test-config.sh
+      - name: run Vim config parity harness
+        run: ./development/tests/test-config-vim.sh