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
 ;; ECOSYSTEM.scm - Project ecosystem positioning
 
 (ecosystem
@@ -9,6 +9,6 @@
    (position-in-ecosystem . "supporting")
    (related-projects
      ((rhodium-standard . "sibling-standard")
-      (gitvisor . "infrastructure")))
+      (git-hud . "infrastructure")))
    (what-this-is . ("A hyperpolymath project"))
    (what-this-is-not . ("A standalone solution"))))

META.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: AGPL-3.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; META.scm - Project metadata and architectural decisions
 
 (define project-meta

STATE.scm

@@ -1,5 +1,5 @@
 ;; STATE.scm - RSR State File
-;; SPDX-License-Identifier: AGPL-3.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; Copyright (C) 2025 Jonathan D.A. Jewell
 ;;
 ;; This file tracks the current state of the project using S-expressions.