affinity: AI-optimize MCP action set

Affinity today has no actions at all — the integration only has account auth wired up. An agent can't read or write anything in the CRM: no contacts, no organizations, no deal pipeline. We'd like a full action set built from scratch so an agent can work with the core CRM objects, and so each tool is easy for an agent to configure.

A few things an agent can't do today, for example:
- Create, get, update, or list persons (contacts)
- Create, get, update, or list organizations
- Create, get, update, or list opportunities (deals)
- Add or remove entries from a list

**API reference:** https://api-docs.affinity.co/

**Add marker:**
When a component is AI-optimized, add this as the first line of the file:
```
// x-pd-ai: optimized
```
Add it to each action file and to the app's `.mjs` file.

Start with the existing Affinity integration and its authentication entry point, then use the Affinity API reference to map the CRM objects and list operations. Add action files for persons, organizations, opportunities, and list membership, plus the app's .mjs file, with the required marker. Done means the listed create, get, update, list, add, and remove operations are available and each relevant file is marked.

Written by the indexing model from the issue text.