fix(a2ml): reconcile media type to application/vnd.a2ml — unblocks IANA submission (#554)

Clears the last in-repo blocker to the **IANA media-type submission**.

## What I found

`a2ml/IANA-MEDIA-TYPE-APPLICATION.md` is a **complete, 259-line RFC 6838
vendor-tree application** for `application/vnd.a2ml` (rev 2, 2026-04-03,
*"Status: Draft — ready for submission"*). Its own checklist already
ticks *fields reviewed*, *spec links accessible*, *no naming conflict*,
and *ASAM A2L (`application/A2L`) distinction clarified*. The only
unticked items are **submit the form → monitor review → record the
assigned type**.

So the registration isn't months of work — it's **an owner action** (the
IANA web form needs applicant identity). But the repo contradicted its
own application in four places:

| name | uses | status |
|---|---|---|
| `application/vnd.a2ml` | 27 | ✅ the application doc's name |
| `text/a2ml` | 5 | ❌ incl. the **normative SPEC** |
| `application/vnd.a2ml+text` | 3 | ❌ `+text` is not a registered
structured-syntax suffix (RFC 6838 §4.2.8) |
| `application/a2ml` | 1 | ❌ standards-tree name — would need IETF
review, not the vendor tree |

A submission contradicted by its own normative spec invites
expert-review pushback, so this reconciles all four to the application
doc's name.

## Deliberately **not** touched
- `a2ml/archive/SPEC-v1.0.0.adoc` (×2) — frozen historical record; the
old name is *correct* there.
- `a2ml/RECORD-DIALECT-SPEC.adoc` §14 — it knowingly documents the
inconsistency and defers resolution to maintainers. Worth a small
editorial update **once IANA assigns the type**.

## Verification
`build-registry.sh --check` ✅ and `build-scorecards.sh --check --strict`
✅ locally. `REGISTRY.a2ml` regenerated because `SPEC.adoc` is
registry-tracked — which also clears the registry drift currently red on
main.

## ⚠️ Related risk for K9 (not fixed here)
K9's **dominant** name is `application/vnd.k9+nickel` (41 uses vs 11
bare `application/vnd.k9`). `+nickel` also does not appear in IANA's
Structured Syntax Suffix registry. **Verify before submitting K9** — if
unregistered, register bare `application/vnd.k9` and keep `+nickel` as
documentation, or pursue a separate suffix registration (slow; depends
on upstream Nickel).

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: hyperpolymath

.machine_readable/REGISTRY.a2ml

@@ -45,7 +45,7 @@ name = "A2ML — Attested Markup Language"
 stream = "foundation"
 home = "a2ml/"
 canonical_doc = "a2ml/README.adoc"
-source_hash = "sha256:215dd1cc7dd184922d6cb04957cd17dfccb7f00ea78252ff5a53634d67851980"
+source_hash = "sha256:3409e79367d002ba52f4ed1742b2846c1beffdf8acf78c53997a69a32bd46617"
 route = "the typed/verified machine-readable document format"
 
 [[spec]]
@@ -54,7 +54,7 @@ name = "K9 Self-Validating Components"
 stream = "foundation"
 home = "k9-svc/"
 canonical_doc = "k9-svc/README.adoc"
-source_hash = "sha256:84313508e94620b1fb70a853d49e9e080d93ff8413475caaaf0eb64db499a69f"
+source_hash = "sha256:9637f4fd9e24d12035da75a719d52127eb1993b206954acde7b576a8a7ad2e96"
 route = "self-validating components with embedded contracts + deploy logic"
 
 [[spec]]
@@ -72,7 +72,7 @@ name = "META.a2ml spec"
 stream = "foundation"
 home = "meta-a2ml/"
 canonical_doc = "meta-a2ml/README.adoc"
-source_hash = "sha256:4b00ebf2fa1ab6aee46b67be34715b4198d4643ce2025c82882afda502d9c038"
+source_hash = "sha256:f5a4aa91b2917ab1945addac2fef904f3b2958240743f2b00a1fbc0f6aca946c"
 route = "architecture decisions / governance metadata format"
 
 [[spec]]
@@ -135,7 +135,7 @@ name = "0-AI Gatekeeper Protocol"
 stream = "protocol"
 home = "0-ai-gatekeeper-protocol/"
 canonical_doc = "0-ai-gatekeeper-protocol/README.adoc"
-source_hash = "sha256:a5bb4eaac86202798bd47f7e403c6f95fcf1c95ee517e8930a599983a1dd8c64"
+source_hash = "sha256:9129453f1962a3cea37702d04e7e8eea353873987dd3e764f8217a045803640d"
 route = "the AI-agent entry/gating protocol behind 0-AI-MANIFEST"
 
 [[spec]]
@@ -152,8 +152,8 @@ id = "avow-protocol"
 name = "AVOW Protocol"
 stream = "protocol"
 home = "avow-protocol/"
-canonical_doc = "avow-protocol/README.adoc"
-source_hash = "sha256:ca167dc32551b71450176b9f9f7538c165b55ce19ee31f5cb7a334affd4edb3c"
+canonical_doc = "avow-protocol/BINDING.adoc"
+source_hash = "sha256:ed5b1c9415c137348313f6d8a65d0d6eb320abf2f64e76bb25e108d7a21a3b5b"
 route = "consent-attested messaging / origin attribution"
 
 [[spec]]
@@ -162,7 +162,7 @@ name = "AXEL Protocol"
 stream = "protocol"
 home = "axel-protocol/"
 canonical_doc = "axel-protocol/README.adoc"
-source_hash = "sha256:326c47a6ca32531d4acff17aaf0313b7579a9d5749429f72f97e907af1fa8d33"
+source_hash = "sha256:020e11cbab41cc5cb86182bc6ba93b58ee6b9bf29237d172e735363eebc5f27c"
 route = "age-gating + explicit-content enforcement"
 
 [[spec]]
@@ -180,7 +180,7 @@ name = "Consent-Aware HTTP"
 stream = "protocol"
 home = "consent-aware-http/"
 canonical_doc = "consent-aware-http/README.adoc"
-source_hash = "sha256:d5cee84e0bccc969cbc76cd17cbf18e6835750a5e664788a4a96f5b50f5fdb2a"
+source_hash = "sha256:a646ae072372fe62bf3fcffa80b1a196f1fe3b9df8e7be4fc5e54be49426b022"
 route = "consent headers / AI-usage boundaries for HTTP"
 
 [[spec]]
@@ -225,7 +225,7 @@ name = "RSR — Rhodium Standard Repositories"
 stream = "governance"
 home = "rhodium-standard-repositories/"
 canonical_doc = "rhodium-standard-repositories/README.adoc"
-source_hash = "sha256:d196156cc4fdade946fab21b87ba4fa076106186bbf59c23fb21fb1cfd64e219"
+source_hash = "sha256:03252ce83c0361887c6a96530c8bba15c4c7f816c07d6d2ffbffd53250e3bf61"
 route = "the repository-compliance standard every repo is graded against"
 
 [[spec]]

a2ml/READINESS.md

@@ -60,7 +60,7 @@
 - Core schema stable since v1.0
 - Referenced by 6 language implementations (Rust, Elixir, Gleam, Haskell, Deno, Julia)
 - Deployed on 105+ repos as the canonical AI manifest format
-- IANA media type submission in progress (`application/vnd.a2ml+text`)
+- IANA media type submission in progress (`application/vnd.a2ml`)
 
 **Known limitations:**
 - PLAYBOOK.a2ml schema at v0.9 (not yet stable)

a2ml/SPEC.adoc

@@ -25,7 +25,7 @@ modes and acquires meaning only when a profile selects it.
 
 [cols="1,3"]
 |===
-| Media Type    | `text/a2ml` (registration pending)
+| Media Type    | `application/vnd.a2ml` (registration pending)
 | File Extension| `.a2ml`
 | Version       | 1.1.0 (Stable)
 | Era           | v1
@@ -685,7 +685,7 @@ evidence of *validation intent*, never of *granted capability*.
 
 == 13. IANA Considerations
 
-Proposed media type `text/a2ml`; file extension `.a2ml`; no magic number;
+Proposed media type `application/vnd.a2ml`; file extension `.a2ml`; no magic number;
 fragment identifier `#section-id`. See the separate IANA registration document.
 
 == 14. Interoperability

a2ml/site/spec.md

@@ -20,7 +20,7 @@ The current normative specification is **A2ML v1.1.0** — Surface Grammar + Typ
 - **Syntax modules** (opt-in)
 - **Grammar appendix**
 - **Conformance + test vectors**
-- **IANA media type draft** — `application/a2ml`
+- **IANA media type draft** — `application/vnd.a2ml`
 - **Comparison matrix**
 - **Citation guide**