feat(instagram): harden api connector for CG rollout

[tnunamak]

Summary

• harden instagram-api-playwright for a consumer rollout on top of Kahtaf's branch
• bubble invalid credentials back through requestInput, preserve OTP/challenge handling, and emit auth_state breadcrumbs
• add requested-scope support plus partial-result/export-summary semantics so CG can switch to the API connector without a local Instagram fork

Details

• respect page.requestedScopes() and only collect requested scopes
• classify auth outcomes (invalid_credentials, otp_required, checkpoint_required, manual_verification_required, etc.) and persist them via page.setData("auth_state", ...)
• keep richer API-first Instagram payloads, including the new instagram.followers scope
• emit a canonical result envelope with requestedScopes, platform, version, exportSummary, and errors
• bump instagram-api-playwright to 2.0.0 and publish a branch artifact/index entry for downstream testing
• make the index generator preserve committed historical entries instead of repackaging every unchanged connector on the current branch

Validation

• node --check connectors/meta/instagram-api-playwright.js
• node scripts/validate-manifests.mjs
• node scripts/validate-scope-schemas.mjs
• node scripts/normalize-manifests.mjs --check
• BASE_REF=origin/main node scripts/check-page-api-additive.mjs
• BASE_REF=origin/main node scripts/check-source-id-stability.mjs
• node scripts/check-additive-schemas.mjs
• node scripts/schema-health-check.mjs --local-only
• node scripts/generate-connector-index.mjs --check
• node skills/vana-connect/scripts/validate.cjs connectors/meta/instagram-api-playwright.js