fix(coordination): restore missing .gitmodules for absolute-zero submodule (#117)

## What & why

The `absolute-zero/` gitlink (`160000 commit ad085ba`) was recorded in
the index, but `.gitmodules` was never committed — leaving a **dangling
submodule pointer**. As a result `git submodule` could not resolve it,
and the Mustfile `submodule-recorded` check (`severity = "critical"`)
always failed.

Eight machine-readable contractiles (Mustfile, Bustfile, Dustfile,
Intentfile, Trustfile, gitbot-fleet, hypatia) document `absolute-zero/`
as a **pinned git submodule (PR #89)**. Only the README contradicted
them ("referenced, not vendored as a submodule"). This PR resolves the
contradiction in favour of the documented majority intent.

## Changes
- Add `.gitmodules` pinning `absolute-zero` to
`https://github.com/hyperpolymath/absolute-zero.git`.
- Reconcile the README status paragraph to describe it as a pinned
submodule (matching ROADMAP, the contractiles, and PR #89).

## Verification
- `git config -f .gitmodules submodule.absolute-zero.url` now succeeds →
the critical `submodule-recorded` check passes.
- `git submodule status` resolves the pinned pointer.

## Context
This is task **A1** of a broader estate assessment (the coordination fix
that unblocks a fresh clone reaching the CNO foundation). Part of a
documentation/coordination honesty pass across the estate. Draft pending
human review.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_015qwVESTcbfanY2iJPQNoSz

---
_Generated by [Claude
Code](https://claude.ai/code/session_015qwVESTcbfanY2iJPQNoSz)_

Co-authored-by: Claude <noreply@anthropic.com>

Author: hyperpolymath

.gitmodules

@@ -0,0 +1,8 @@
+# The Certified Null Operation (CNO) reference is developed in the standalone
+# hyperpolymath/absolute-zero repository and pinned here as a submodule (PR #89).
+# CNO development happens upstream; this pointer is bumped as a deliberate act
+# (see .machine_readable/contractiles/Intentfile.a2ml and Trustfile.a2ml).
+[submodule "absolute-zero"]
+	path = absolute-zero
+	url = https://github.com/hyperpolymath/absolute-zero.git
+	branch = main

README.md

@@ -21,9 +21,11 @@ secure, and sustainable systems.
 > 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.
+> developed in the standalone `hyperpolymath/absolute-zero` repository and
+> pinned here as a git submodule under `absolute-zero/` (PR #89) — CNO
+> development happens upstream, and this pointer is bumped deliberately. A
+> CRG Tier-C test suite (unit, E2E, property, aspect, benchmarks) landed
+> 2026-04-04.
 > Detailed specification documents will be uploaded as development
 > progresses.