docs: bedroom developer documentation — complete docs/developers/ set

Adds the full bedroom-developer-docs OpenSpec change implementation:

- docs/developers/README.md — index page
- docs/developers/quick-start.md — bootstrap to working token in 7 steps
- docs/developers/concepts.md — AgentIdP, AGNTCY, lifecycle, OAuth 2.0, free tier
- docs/developers/guides/README.md — guide index
- docs/developers/guides/register-an-agent.md — all fields, validation, common errors
- docs/developers/guides/manage-credentials.md — generate, list, rotate, revoke
- docs/developers/guides/issue-and-revoke-tokens.md — OAuth 2.0 flow, introspect, revoke
- docs/developers/guides/query-audit-logs.md — filters, pagination, 90-day retention
- docs/developers/api-reference.md — all 14 endpoints, all error codes, curl examples

Also commits deferred OpenSpec housekeeping from previous session:
- Archives phase-1-mvp-implementation change to openspec/changes/archive/
- Adds bedroom-developer-docs change artifacts (30/30 tasks complete)
- Syncs 4 delta specs to openspec/specs/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/developers/README.md

@@ -0,0 +1,42 @@
+# SentryAgent.ai AgentIdP — Developer Documentation
+
+The complete documentation for bedroom developers building with SentryAgent.ai AgentIdP.
+
+## What is this?
+
+SentryAgent.ai AgentIdP is a free, open-source Identity Provider built specifically for AI agents. Your agent gets a unique ID, OAuth 2.0 credentials, and a full audit trail — for free.
+
+## Documents
+
+| Document | What it covers |
+|----------|----------------|
+| [Quick Start](quick-start.md) | Register your first agent and issue a token in under 5 minutes |
+| [Core Concepts](concepts.md) | What AgentIdP is, how it works, and why you need it |
+| [Guides](guides/README.md) | Step-by-step walkthroughs for each workflow |
+| [API Reference](api-reference.md) | Every endpoint, field, error code, and example |
+
+## Guides
+
+| Guide | What it covers |
+|-------|----------------|
+| [Register an Agent](guides/register-an-agent.md) | All fields, validation rules, common errors |
+| [Manage Credentials](guides/manage-credentials.md) | Generate, list, rotate, revoke credentials |
+| [Issue and Revoke Tokens](guides/issue-and-revoke-tokens.md) | OAuth 2.0 client credentials flow, introspect, revoke |
+| [Query Audit Logs](guides/query-audit-logs.md) | Filters, pagination, event structure, retention |
+
+## Base URL
+
+```
+http://localhost:3000/api/v1   # local development
+```
+
+All endpoints require a Bearer token in the `Authorization` header unless noted otherwise.
+
+## Free Tier Limits
+
+| Resource | Limit |
+|----------|-------|
+| Registered agents | 100 |
+| Token requests/month | 10,000 |
+| API rate limit | 100 req/min |
+| Audit log retention | 90 days |