Add ppl plugin to marketplace

[dbhurley]

Submission

Adds the ppl plugin (https://github.com/ppl-crm/ppl-grok-plugin) to the marketplace catalog.

ppl is the personal CRM for AI agents: a hosted MCP server (https://withppl.com/mcp, 85 tools, Streamable HTTP) giving Grok Build agents durable memory of the people who matter: briefings, notes, reminders, tasks, calls, gifts, and journal entries. No local install or downloadable server; the plugin config points at the hosted endpoint. The agent guides the user through the one-approval connect flow at https://withppl.com/agents on first connect, so no manual token handling is needed.

Checklist

• One entry added to .grok-plugin/marketplace.json, valid JSON, name in kebab-case and unique
• Remote source pins a full 40-char lowercase commit sha (d60db65c809767c39dadab6957421f90b1657b38); commit is public and reachable
• .grok-plugin/plugin-index.json regenerated and committed (never hand-edited)
• homepage and clear description; brand-scoped keywords/domains (ppl, withppl.com only); category: productivity
• Plugin is MIT licensed; license stated in source repo
• Local validation run (the same checks CI runs):
  • python3 scripts/validate-catalog.py -> Catalog OK
  • python3 scripts/generate-plugin-index.py --check -> Plugin index OK
• Source is the official ppl-crm org, matching the ppl brand
• Security expectations reviewed: the plugin declares an MCP HTTP server config only; no code execution, no RCE, no secret exfiltration, no telemetry

[dbhurley]

Hi! Just a friendly follow-up: this PR is ready for review and checks are passing. Happy to adjust anything in the plugin manifest or listing if needed. Thanks!