chore(dx): consolidate commands behind make + add editor config

- Make is the canonical interface; pnpm scripts wrap turbo, make wraps pnpm
- CI now calls `make ci-web` / `make ci-desktop` so local == CI
- Add .nvmrc (node 24, matches CI) + engines field
- Add .editorconfig and .vscode (extensions + settings)
- Add `pnpm bootstrap` (deps + Playwright Chromium)
- Add `dev:web` / `dev:desktop` shortcuts
- CONTRIBUTING.md: lead with `make bootstrap`/`make dev-web`,
  link Tauri prereqs, fix wrong `pnpm dev` claim
- CLAUDE.md: command table reflects make-first workflow

.editorconfig

@@ -0,0 +1,19 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+trim_trailing_whitespace = true
+indent_style = tab
+indent_size = 2
+
+[*.{md,mdx}]
+trim_trailing_whitespace = false
+
+[*.{yml,yaml,toml}]
+indent_style = space
+indent_size = 2
+
+[*.json]
+indent_style = tab