feat(oc-docs): migrate response formatter + preview from bruno-app

[vasharma05-bruno]

Summary

Migrates the response-formatter UI from bruno-app into oc-docs and wires it into the playground response pane.

• MenuDropdown — faithful port of bruno-app's dropdown (Tippy-backed, keyboard nav, grouped/flat items, submenus, controlled/uncontrolled state), fully typed. Adds an itemToText-driven default trigger so it can display the selected item without a children trigger.
• QueryResultPreview — ported for the web-feasible subset: HTML (sandboxed <iframe>, replacing the Electron <webview>), JSON (@microlink/react-json-view), XML tree, and text. Binary previews (image/pdf/audio/video) are omitted because the docs response has no data buffer.
• Response format selector — rebuilt on MenuDropdown with grouped formats and a Preview toggle in the dropdown header; useResponseFormatter split into its own module.
• ResponseBodyTab — renders the preview when the toggle is on, otherwise the read-only editor.

Notable decisions

• Used @microlink/react-json-view instead of bruno's react-json-view (peer react <= 17), which silently downgraded oc-docs to React 17 in this monorepo; a global override isn't viable since oc-spec-site is on React 19. The fork is API-identical with peer react >= 15.
• Added a tsconfig paths entry so @tabler/icons type declarations resolve (its exports map has no types condition).

Follow-ups

Deferred work is tracked in packages/oc-docs/improvements.md (binary previews, dropping tippy/tabler, reusable Toggle, etc.).

Verification

• tsc --noEmit: 0 errors
• eslint --max-warnings 0: clean
• vitest: passing (MenuDropdown + QueryResultPreview)

🤖 Generated with Claude Code

[vasharma05-bruno]

Rebased onto main. Because main since removed PlaygroundDrawer/ and restructured everything under Playground/Content/Views/, a literal commit-by-commit rebase wasn't viable (the old commits added files at now-deleted paths). Instead this is re-applied onto main's current structure as one clean commit:

• MenuDropdown is now taken from main (it landed separately via feat(oc-docs): migrate native selects to MenuDropdown #113/fix(oc-docs): MenuDropdown review feedback, listbox ARIA, and dropdown stacking above the docks #121) — this PR no longer vendors it.
• Preview components live under Playground/QueryResult/; the format selector + useResponseFormatter wire into ResponsePane (keeping main's StyledWrapper).
• react-json-view is lazy-loaded and browser-only so it doesn't crash SSR (server bundle / renderToStaticMarkup unit tests).
• Dropped the .prettierrc and improvements.md additions (repo has no Prettier / no scratch files).

Validation: lint clean on touched files, test:run 917/917 pass (added QueryResultPreview.spec.tsx). Page-level e2e isn't feasible (the preview only appears after a request, and sending aborts under the Vite dev server) — preview logic is covered by unit tests.