docs: add checkpoint files for state tracking

Add STATE.scm, ECOSYSTEM.scm, and META.scm for project state management:
- STATE.scm: Current project state, tasks, blockers, milestones
- ECOSYSTEM.scm: Relationships to other projects in ecosystem
- META.scm: Architectural decisions and development practices

These files enable AI assistants and tools to understand project
context and make informed decisions about changes.

Part of RSR (Rhodium Standard Repository) compliance.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Test

ECOSYSTEM.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: AGPL-3.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; SPDX-FileCopyrightText: 2025 Jonathan D.A. Jewell
 ;; ECOSYSTEM.scm — robot-vacuum-cleaner
 

META.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: AGPL-3.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; SPDX-FileCopyrightText: 2025 Jonathan D.A. Jewell
 ;;; META.scm — robot-vacuum-cleaner
 

STATE.scm

@@ -1,5 +1,5 @@
 ;;; STATE.scm — robot-vacuum-cleaner
-;; SPDX-License-Identifier: AGPL-3.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; SPDX-FileCopyrightText: 2025 Jonathan D.A. Jewell
 
 (define metadata