[codex] Expose research MCP tools

[mogery]

Summary

• Expose Firecrawl research MCP tools without FIRECRAWL_RESEARCH or ?research=true gating
• Point tools at the canonical /v2/search/research route
• Use camelCase tool arguments and response fields such as paperId and poolSize

Impact

Research tools are always registered and visible through MCP transports. Tool argument names now match the camelCase API contract.

Validation

• npm run build
• rg FIRECRAWL_RESEARCH/isResearchEnabled/?research=true/session.research/canAccess over src and dist
• git diff --check

No tests were run.