fix: migrate to PMPL-1.0-or-later license

- Add LICENSE file (PMPL-1.0-or-later full text)
- Update README.adoc license section (remove AGPL references)
- Fix SPDX headers in checkpoint files (STATE.scm, ECOSYSTEM.scm, META.scm)
- Remove LICENSE-PALIMPS.md stub (0 bytes)
- Add integration documentation (ECHIDNA, roadmap, license audit)

BREAKING CHANGE: License changed from AGPL-3.0 to PMPL-1.0-or-later

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

Author: Jonathan D.A. Jewell

.machine_readable/AGENTIC.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: MPL-2.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; AGENTIC.scm - AI agent interaction patterns for absolute-zero
 
 (define agentic-config

.machine_readable/ECOSYSTEM.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: MPL-2.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; ECOSYSTEM.scm - Ecosystem position for absolute-zero
 ;; Media-Type: application/vnd.ecosystem+scm
 

.machine_readable/META.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: MPL-2.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; META.scm - Meta-level information for absolute-zero
 ;; Media-Type: application/meta+scheme
 

.machine_readable/NEUROSYM.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: MPL-2.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; NEUROSYM.scm - Neurosymbolic integration config for absolute-zero
 
 (define neurosym-config

.machine_readable/PLAYBOOK.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: MPL-2.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; PLAYBOOK.scm - Operational runbook for absolute-zero
 
 (define playbook

.machine_readable/STATE.scm

@@ -1,4 +1,4 @@
-;; SPDX-License-Identifier: MPL-2.0-or-later
+;; SPDX-License-Identifier: PMPL-1.0-or-later
 ;; STATE.scm - Project state for absolute-zero
 ;; Media-Type: application/vnd.state+scm