Proposal: Multi-developer configuration for distributed teams

[marcoaperez]

This adds a design proposal at docs/proposals/multi-developer-config.md covering how to support multiple developers working against the same FMS-hosted solution — each from their own machine, with their own local agentic-fm repo and their own companion server — without having to edit FM scripts for every person on the team.

Context

Get agentic-fm path currently assumes one developer per solution (caches the chosen folder in $$AGENTIC.FM for the session), and Explode XML hardcodes the companion URL to http://localhost:8765. With the exclusive-bind policy where COMPANION_BIND_HOST points at a LAN or Tailscale address instead of 127.0.0.1, localhost returns "Connection refused", and teams end up with a chain of If Get(AccountName) = "..." branches inside the script — a hardcoded path and companion IP per developer, edited directly into the .fmp12.

That workaround doesn't scale, mixes environment config with package logic, and forces machine-specific data to live inside the solution file instead of in the repo where it belongs.

Proposal

Full writeup in docs/proposals/multi-developer-config.md. Short version:

• Move per-developer config to an optional users section in automation.json (already lives next to each developer's companion).
• Add a GET /whoami endpoint to the companion server that reads that section and returns the block for the current account.
• Refactor Get agentic-fm path to cascade: cached global → companion /whoami → optional agentic_fm_users FM table → interactive dialog fallback.
• Parametrize Explode XML's URL with $$AGENTIC.FM.COMPANION.HOST / $$AGENTIC.FM.COMPANION.PORT globals populated by Get agentic-fm path.

All fully backward-compatible — solo developers see no functional change, everything is opt-in.

What this PR contains

Just the markdown writeup under docs/proposals/. If the direction lands well, I'm happy to follow up with the implementation PRs, split by component (automation.json schema, companion_server.py endpoint, FM script refactors, and the filemaker/README.md section).