Add gotchas links + 17 proxy-only connector skills

[Gdewilde]

Summary

Two related catalog improvements that grow the connector catalog from 146 → 163 and expose Apideck's per-connector "gotchas" pages everywhere:

• Gotchas links on every unified-API connector skill (146 skills). Each `Quick facts` block now links to `https://developers.apideck.com/apis/{unifiedApi}/{slug}/gotchas\`. Multi-API connectors (workday, odoo, sage-hr, sap-successfactors) emit one link per API. Three known-missing pairs (`freshteam` × hris/ats, `silae-fr` × hris) suppress the line via `noGotchas: true` on the manifest entry.
• 17 new proxy-only connector skills for connectors Apideck flags as `auth_only: true` with zero supported resources. These route through the Proxy API + Vault auth, not a unified resource API — the skill teaches the `x-apideck-downstream-url` call shape and lets the agent keep using the vendor's native request/response format. New `renderProxyOnlySkill()` template; dispatch on `proxyOnly: true` in the manifest. Connectors: Asana, Azure DevOps, Basecamp, ClickUp, Intercom, JetBrains YouTrack, Jira Data Center, Jira Service Desk, Jira Teams, Mollie, monday.com, Notion, Sage Intacct REST, ServiceNow, Sesame HR, Shortcut, Zendesk.

Validator passes 163/163 (0 errors, 0 warnings). README + `llms.txt` updated to reflect the new total and call out the proxy-only family.

Test plan

• `node connectors/generate.js` writes 163 SKILL.md files
• `node connectors/validate.js` passes 163/163
• `node skills/sync.js --skills-only --connectors` mirrors to `providers/claude/plugin/skills/` and `providers/cursor/plugin/skills/`
• All 146 unified-API gotchas URLs verified via `<title>` (149 of 152 connector × API combos exist; 3 flagged `noGotchas`)
• All 17 proxy-only `/apis/proxy/{slug}/gotchas` URLs verified
• Spot-check a Tier 1a skill (e.g. `skills/quickbooks/SKILL.md`) renders the new gotchas line correctly
• Spot-check a proxy-only skill (e.g. `skills/notion/SKILL.md`) reads end-to-end

🤖 Generated with Claude Code