Add portable ego plugin and restore cross-round OOPIFs

[section9-lab]

Summary

• add a portable, Skill-only ego plugin package for supported agent hosts and keep it synchronized with the canonical ego-browser Skill 1.4.0
• restore existing and nested OOPIF Playwright sessions after TaskSpace round reconnects while preserving safe transport shutdown and TaskSpace isolation
• add routing regressions and a real-browser cross-round test that clicks the innermost OOPIF zoom control and verifies the map state changes

Integration

• rebased onto the latest sprint-1.3.0
• kept the upstream outer-timeout policy and dropped the superseded local assertion
• synchronized the portable Skill, plugin manifests, marketplace metadata, README, and tests with the upstream Skill update

Validation

• npm test: 550 passed, 6 skipped, 0 failed
• focused cross-round OOPIF E2E: 4/4 cases passed, 46 assertions
• focused agent mouse overlay E2E: 4/4 cases passed, 40 assertions
• plugin and Skill validators passed
• portable plugin tests: 32/32 passed