chore: .scm -> .a2ml for 6a2 files (canonical location) + Justfile make -> just (#29)

## Summary

Two related fixes per estate language/build policy:

1. **`.scm` → `.a2ml` for the 6a2 metadata files**, relocated from repo
root into the canonical `.machine_readable/6a2/` location.
2. **`make` → `just` in the Justfile**: existing recipes called `make`
for inter-recipe orchestration, but Makefiles are forbidden estate-wide
(per `hypatia-rules/rsr-self-compliance.a2ml @forbidden_files`
`Makefile` "Use Justfile") — and there's no Makefile in this repo
regardless, so `make` calls would simply fail.

## What changed

### `.scm` → `.a2ml`, root → `.machine_readable/6a2/`

Per the user-confirmed estate rule (2026-04-30): *".a2ml is canonical;
.scm is reserved for Guix-related files only."* The 6a2 metadata files
were at the repo root with `.scm` extensions — they are now at the
canonical RSR location with `.a2ml` extensions.

| Old | New |
|---|---|
| `STATE.scm` | `.machine_readable/6a2/STATE.a2ml` |
| `META.scm` | `.machine_readable/6a2/META.a2ml` |
| `ECOSYSTEM.scm` | `.machine_readable/6a2/ECOSYSTEM.a2ml` |
| `AGENTIC.scm` | `.machine_readable/6a2/AGENTIC.a2ml` |
| `NEUROSYM.scm` | `.machine_readable/6a2/NEUROSYM.a2ml` |
| `PLAYBOOK.scm` | `.machine_readable/6a2/PLAYBOOK.a2ml` |

**Content format unchanged.** A2ML is a format family; the S-expression
/ SRFI-30 surface used by these files (per the
`playbook-a2ml/spec/PLAYBOOK-FORMAT-SPEC.adoc` schema reference at the
top of each) is a legitimate A2ML dialect alongside the TOML-like
dialect used elsewhere. Only the file extension changes; the canonical
S-expression Scheme content is preserved.

### Pre-existing duplicate STATE.a2ml

The repo previously had `.machine_readable/6a2/STATE.a2ml` as a
"secondary short-form companion" (per its own header), with the
top-level `STATE.scm` marked as the canonical authority. The
maintainer's note in that file explicitly planned the migration:

> _"To migrate to a single canonical surface in a future session, the
(lifecycle ...) block should be moved into PLAYBOOK.scm (a sibling of
STATE.scm, in the (define ...) module shape) and this file then deleted.
That migration is parked, not blocking."_

This PR executes that parked migration:

- The unique `(lifecycle ...)` block from the old secondary `STATE.a2ml`
is appended to the new `.machine_readable/6a2/PLAYBOOK.a2ml` (with a
header comment noting the migration source).
- The new canonical `.machine_readable/6a2/STATE.a2ml` is the content
from the former top-level `STATE.scm`.

### Headers updated

The first line of each moved file's header was updated from `<NAME>.scm`
to `<NAME>.a2ml` to match the new filename. Cross-references *within*
the file content (e.g. `audit-output/STATE.scm`, `META.scm
pre-action-checks`) are deliberately left as-is in this PR — they are
content-prose references that need separate judgement on path/extension
and are scoped for a follow-up.

### Justfile: `make` → `just`

Several recipes called `make build-tests`, `make test-core`, etc. —
invoking the `make` binary against a non-existent Makefile. These are
now `just build-tests`, `just test-core`, etc., correctly invoking
sibling Just recipes. No change in semantics for any working recipe;
broken recipes (silently failing on missing Makefile) now actually run.

## Why two fixes in one PR

Both are small, both are policy-alignment, both relate to "what
canonical builds look like for echo-types." Splitting them into two PRs
would be over-process. Each is reviewable independently in the diff.

## Out of scope (follow-up PRs)

- The full RSR floor (28 missing files: CHANGELOG.md /
CODE_OF_CONDUCT.md / SECURITY.md / CONTRIBUTING.md / EXPLAINME.adoc /
QUICKSTARTs / TOPOLOGY.adoc / 0-AI-MANIFEST.a2ml / stapeln.toml /
Containerfile / dotfiles / contractiles/ etc.) — separate PR.
- Conversion of `README.md` / `roadmap.adoc` / `roadmap-gates.adoc` /
`DOCUMENTATION_STATUS.md` etc. to canonical RSR shapes — separate PR.
- The mandatory 4 RSR workflows (`hypatia-scan.yml`, `mirror.yml`,
`scorecard.yml`, `rsr-antipattern.yml` per
`hypatia-rules/rsr-self-compliance.a2ml @required_workflows`) —
currently this repo has only `agda.yml`. Separate PR.
- Prose `.scm` references inside the migrated 6a2 files
(path-and-extension dual update) — separate small PR after this lands.

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

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

AGENTIC.scm .machine_readable/6a2/AGENTIC.a2mlAGENTIC.scm renamed to .machine_readable/6a2/AGENTIC.a2ml

@@ -1,5 +1,5 @@
 ;;; ============================================================
-;;; AGENTIC.scm — gating rules for echo-types operational requests
+;;; AGENTIC.a2ml — gating rules for echo-types operational requests
 ;;; ============================================================
 ;;;
 ;;; Format: agentic-a2ml (S-expression, SRFI-30 conventions)

ECOSYSTEM.scm .machine_readable/6a2/ECOSYSTEM.a2mlECOSYSTEM.scm renamed to .machine_readable/6a2/ECOSYSTEM.a2ml

@@ -1,5 +1,5 @@
 ;;; ============================================================
-;;; ECOSYSTEM.scm — echo-types relationships across the
+;;; ECOSYSTEM.a2ml — echo-types relationships across the
 ;;; hyperpolymath repository constellation
 ;;; ============================================================
 ;;;

META.scm .machine_readable/6a2/META.a2mlMETA.scm renamed to .machine_readable/6a2/META.a2ml

@@ -1,5 +1,5 @@
 ;;; ============================================================
-;;; META.scm — echo-types architecture decisions from EI-2
+;;; META.a2ml — echo-types architecture decisions from EI-2
 ;;; ============================================================
 ;;;
 ;;; Format: meta-a2ml (S-expression, SRFI-30 conventions)

NEUROSYM.scm .machine_readable/6a2/NEUROSYM.a2mlNEUROSYM.scm renamed to .machine_readable/6a2/NEUROSYM.a2ml

@@ -1,5 +1,5 @@
 ;;; ============================================================
-;;; NEUROSYM.scm — formal-evidence semantics for EI-2 termination
+;;; NEUROSYM.a2ml — formal-evidence semantics for EI-2 termination
 ;;; ============================================================
 ;;;
 ;;; Format: neurosym-a2ml (S-expression, SRFI-30 conventions)

PLAYBOOK.scm .machine_readable/6a2/PLAYBOOK.a2mlPLAYBOOK.scm renamed to .machine_readable/6a2/PLAYBOOK.a2ml

@@ -1,5 +1,5 @@
 ;;; ============================================================
-;;; PLAYBOOK.scm — operational procedures for echo-types sessions
+;;; PLAYBOOK.a2ml — operational procedures for echo-types sessions
 ;;; ============================================================
 ;;;
 ;;; Format: playbook-a2ml (S-expression, SRFI-30 conventions)
@@ -265,6 +265,26 @@
      (role . "If a 6a2 schema question arises that this PLAYBOOK doesn't resolve.")
      (hours . "asynchronous"))))
 
+;;; ============================================================
+;;; Session lifecycle (migrated from former .machine_readable/6a2/STATE.a2ml
+;;; "secondary short-form companion" file as part of the 2026-04-30
+;;; .scm -> .a2ml migration. The original file's own header marked this
+;;; block as the only unique contribution it carried.)
+;;; ============================================================
+
+(define lifecycle
+  '((on-enter
+     (step . "Read .machine_readable/6a2/STATE.a2ml first")
+     (step . "Read .machine_readable/6a2/META.a2ml for permanent decisions")
+     (step . "Check status.phase before starting any work")
+     (step . "If user asks about EI-2: state TERMINATED; refer to ei-2 block in STATE"))
+    (on-exit
+     (step . "Update status.phase if changed")
+     (step . "Update commits-pushed if any commits actually pushed")
+     (step . "If new questions opened, add to open-questions block in STATE")
+     (step . "If naming-traps encountered, add to naming-traps block in STATE")
+     (step . "Never remove the ei-2 block; it is permanent record"))))
+
 ;;; ============================================================
 ;;; END OF PLAYBOOK
 ;;; ============================================================

.machine_readable/6a2/STATE.a2ml

@@ -20,7 +20,7 @@ build-all:
 	@echo "🔨 Building all echo type modules and tests..."
 	@echo "=========================================="
 	just build-echo
-	make build-tests
+	just build-tests
 	@echo "=========================================="
 	@echo "✅ Build complete! All modules type-check successfully"
 
@@ -57,11 +57,11 @@ test-stability:
 test-all:
 	@echo "🧪 Running comprehensive test suite..."
 	@echo "=========================================="
-	make test-core
-	make test-cno
-	make test-thermo
-	make test-cat
-	make test-stability
+	just test-core
+	just test-cno
+	just test-thermo
+	just test-cat
+	just test-stability
 	@echo "=========================================="
 	@echo "✅ All tests passed! Stability: 92/100"
 
@@ -75,9 +75,9 @@ clean:
 verify:
 	@echo "🔬 Full verification cycle..."
 	@echo "=========================================="
-	make clean
-	make build-all
-	make test-all
+	just clean
+	just build-all
+	just test-all
 	@echo "=========================================="
 	@echo "✅ Verification complete! System stability: 92/100"
 
@@ -103,5 +103,4 @@ stability-report:
 
 # Default target
 default:
-	make verify
-
+	just verify