feat: complete Track B P2 proxy package baseline and smoke guardrails

[sriinnu]

Summary

• add @termina/proxy-runtime, @termina/proxy-axios, and @termina/proxy-got with production baseline APIs, tests, docs/examples, SKILL metadata, and SVG brand assets
• stabilize CI check flow to build package artifacts before cross-package type checks
• update Track B docs/runbooks for P2 creation status and current lockstep counts
• extend consumer smoke verification to include new P2 packages
• fix new package TS config path mappings so published tarballs expose clean dist/index.js entrypoints

Validation

• npm run ci:check
• npm run test:all
• npm run verify:consumer-smoke
• npm run release:proxy:lockstep

Known open release gates (unchanged)

• Gate 1: release-candidate changelog/approval evidence still partial for new @termina/proxy-* candidates
• Gate 2: designated home-Mac validation still open
• Gate 4: release notes + rollback approval artifact still open