remove legacy build pages, unused deps

[vigneshrajsb]

What changed

• remove all Next.js web pages under src/pages/builds/
• delete the page-only src/components/logs and src/components/ai-agent frontend trees that were only used by those routes
• remove the page-only packages that existed only for those routes: axios, partial-json, react-markdown, react-shiki, rehype-raw, and remark-gfm
• remove additional unused packages: @types/react-syntax-highlighter, react-syntax-highlighter, bcryptjs, isomorphic-unfetch, js-cookie, kubernetes-client, seedrandom, inquirer, mockdate, only-allow, and promptfoo
• simplify the activity stream status table back to Service / Branch / Status so it no longer emits links to removed /builds/... pages
• remove stale jest.mock('axios') setup from the GitHub test files

Why

The /builds/* pages are no longer meant to be served from this app. Users navigate to the relevant functionality from a separate UI, so keeping these routes, internal status-comment links, and page-only dependencies in this repo only preserves dead surface area.

Impact

• removes the legacy /builds/:uuid/* web routes from this app
• drops the unused frontend code and additional unreferenced dependencies tied to that surface area or otherwise unused in the repo
• removes dead Build Pipeline and Deploy Logs columns from the activity-stream comment table

Validation

• pnpm exec prettier --check package.json pnpm-lock.yaml
• pnpm run lint
• pnpm run build
• pnpm test