chore(standalone): remove absolute-zero submodule — coordinate, don't vendor

Per the standalone-repos decision: maa-framework no longer vendors the CNO
as a git submodule; it coordinates the standalone hyperpolymath/absolute-zero
repo (untouched in its own repo).

- Removed the absolute-zero submodule gitlink + .gitmodules.
- README: 'absolute-zero/ git submodule' → standalone repo coordinated here;
  dropped the absolute-zero/ entry from the in-tree layout diagram.
- 6a2/ECOSYSTEM.a2ml: position = coordinator; added [related-projects]
  referencing absolute-zero (+ oblibeny) as standalone repos.

No CI/build referenced the submodule path, so pipelines are unaffected.

https://claude.ai/code/session_01GJatEm2TVFSTBEkKXmserJ

Author: claude

.gitmodules

@@ -7,4 +7,10 @@ project = "maa-framework"
 ecosystem = "hyperpolymath"
 
 [position]
-type = "component"
+type = "coordinator"  # maa-framework is the coordinating hub for its ecosystem
+
+[related-projects]
+# Coordinating hub: the projects below are standalone top-level repos,
+# referenced/contextualised here — NOT vendored as submodules.
+absolute-zero = "hyperpolymath/absolute-zero — Certified Null Operation (CNO); standalone repo, coordinated here (submodule removed 2026-06-13)"
+oblibeny = "hyperpolymath/oblibeny — reference language designed for the framework"

.machine_readable/6a2/ECOSYSTEM.a2ml

@@ -19,7 +19,7 @@ toc::[]
 ====
 *Early implementation* — Specification uploads still pending (ROADMAP Phase 1).
 
-This repository serves as the official hub and governance center for the MAA Framework project. Implementation work lives in-tree under `aletheia/` (the microkernel, Rust) and in the `absolute-zero/` git submodule (the Certified Null Operation, pinned to upstream). A CRG Tier-C test suite (unit, E2E, property, aspect, benchmarks) landed 2026-04-04. Detailed specification documents will be uploaded as development progresses.
+This repository serves as the official hub and governance center for the MAA Framework project. Implementation work lives in-tree under `aletheia/` (the microkernel, Rust); the Certified Null Operation is the standalone `hyperpolymath/absolute-zero` repository, coordinated here (referenced, not vendored as a submodule). A CRG Tier-C test suite (unit, E2E, property, aspect, benchmarks) landed 2026-04-04. Detailed specification documents will be uploaded as development progresses.
 ====
 
 == Overview
@@ -69,7 +69,6 @@ The framework addresses the following domains:
 │   └── workflows/         # CI wrappers + multi-forge synchronization
 ├── .machine_readable/     # 6a2 metadata, contractiles, bot directives
 ├── aletheia/              # Microkernel implementation (Rust)
-├── absolute-zero/         # CNO reference (git submodule, pinned)
 ├── tests/                 # E2E, property, aspect tests
 ├── GOVERNANCE.adoc        # Project governance
 ├── README.adoc            # This file