bridge: require registration token for broker registration

[benvinegar]

Summary

• require --registration-token for baudbot broker register
• remove legacy --auth-code parsing and payload support from bin/broker-register.mjs
• update broker registration usage/help text in bin/baudbot
• update docs/examples to use token-only registration flow:
  • README.md
  • CONFIGURATION.md
  • AGENTS.md
  • docs/operations.md
• update broker registration tests for token-only behavior

Why

modem-dev/baudbot-services merged the dashboard-canonical registration flow and /api/register now requires registration_token in the primary path. Keeping auth_code in baudbot caused stale UX/docs and a misleading CLI contract.

Testing

• node --test bin/broker-register.test.mjs
• node --check bin/broker-register.mjs
• bash -n bin/baudbot

[greptile-apps]

Greptile Summary

This PR removes the legacy auth_code registration flow and enforces registration_token as the sole authentication mechanism for broker registration, aligning with the updated /api/register endpoint in baudbot-services.

Key changes:

• Removed --auth-code parameter parsing from bin/broker-register.mjs
• Updated payload to send only registration_token (previously conditionally sent both)
• Removed legacy auth_code error mappings (403 invalid/consumed auth code)
• Added new error mapping for 400 "missing registration proof"
• Updated all documentation files (README.md, CONFIGURATION.md, AGENTS.md, docs/operations.md) with token-only examples
• Updated CLI help text in bin/baudbot to show --registration-token as required
• Added test coverage for token requirement and --auth-code rejection

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• Clean API migration with comprehensive test coverage, consistent documentation updates across all files, and proper error handling. The changes are backward-incompatible by design (removing deprecated auth_code), which is intentional and documented in the PR description
• No files require special attention

Important Files Changed

Filename	Overview
bin/broker-register.mjs	Removed legacy auth_code parameter parsing and payload support, now requires registration_token only
bin/broker-register.test.mjs	Updated tests to validate token-only registration flow and verify auth_code rejection
bin/baudbot	Updated CLI help text to reflect required --registration-token parameter

_{Last reviewed commit: 6ba9064}