* refactor(browser): split browser cores via build ARG, add core selector
- Replace playwright official image with ubuntu:noble base in both
docker/Dockerfile.browser and devenv/Dockerfile.browser; install
browsers at build time driven by ARG/ENV BROWSER_CORES
- Add GET /cores endpoint to Browser Gateway reporting available cores
- Proxy GET /browser-contexts/cores in Go handler to Browser Gateway
- Add `core` field to BrowserContextConfigModel and GatewayBrowserContext;
context creation selects the appropriate browser instance by core
- Frontend context-setting page fetches available cores and renders a
core selector; saves core as part of the config JSON
- install.sh prompts for browser core selection and writes BROWSER_CORES
to .env; builds the browser image locally before docker compose up
- Regenerate OpenAPI spec and TypeScript SDK
* fix: lint
Acbox Liu