fix(connections): harden --of flow and document upstream clamp

[peggyrayzis]

Related

Refs #2

Description

Stabilize connections --of resolution/pagination behavior, remove unused experimental backend, and document the current upstream limitation where LinkedIn can clamp --of results.

Summary

• resolve --of usernames/profile URLs to canonical profile IDs before search requests
• keep stable flagship connections --of flow as the only backend (remove experimental search-dash path)
• harden --of parsing/pagination behavior and tests around sparse/empty page handling
• document upstream connections --of clamp limitation in docs/memory
• update smoke test to run query-ids --json without requiring a local HAR file

Checks

• npm run check
• npm run security
• bash scripts/check-docs.sh
• bash scripts/smoke.sh

Review

• Reviewer findings addressed or documented
• Residual risks documented