Add Xquik provider to Twitter monitor

[kriptoburak]

Summary

• Add optional Xquik provider selection to twitter_monitor while preserving TwitterAPI.io as the auto default when configured
• Add Xquik credential plumbing for core types, CLI env lookup, playground web credentials, and docs MCP
• Add mocked coverage for explicit and auto Xquik monitor searches

Source and duplicate checks

• Verified the Xquik search contract against the published OpenAPI schema: GET /x/tweets/search with q, queryType, limit, x-api-key, and xquik-api-contract: 2026-04-29
• Checked the default branch and open/closed PRs/issues for Xquik, x-twitter-scraper, Xquik-dev, xquik.com, and X Twitter Scraper before opening this PR
• Followed the existing node implementation pattern and kept request timeout/retry behavior through fetchWithRetry

Validation

• npm install --ignore-scripts --no-audit --no-fund --package-lock=false
• npm run build --workspace=@jam-nodes/core
• npm run typecheck --workspace=@jam-nodes/core
• npm run test --workspace=@jam-nodes/nodes -- src/integrations/social/twitter-extended.test.ts
• npm run test --workspace=@jam-nodes/nodes
• npm run build --workspace=@jam-nodes/docs-mcp
• git diff --check

Known target-side blockers

• npm ci is currently blocked by the existing package-lock mismatch around the checked-in zod versions.
• npm run typecheck --workspace=@jam-nodes/nodes is currently blocked by existing unrelated type errors in Apify, Google Sheets, Slack, and executor typing paths.
• npm run typecheck --workspace=@jam-nodes/playground is blocked until @jam-nodes/nodes can build cleanly.