Make the README a front door instead of a specification cover page

.github/CODEOWNERS

@@ -9,17 +9,24 @@
 # catch-all.
 
 #
-# WHY THESE PATHS NAME TWO OWNERS AND NOT ONE.
+# WHY THESE PATHS NAME TWO ACCOUNTS AND NOT ONE.
 #
 # They named only @0j0bit until 2026-09-12. That deadlocks: GitHub does not let
 # anyone approve their own pull request, and the branch ruleset grants no
 # bypass to administrators, so a pull request touching one of these paths and
 # authored by its sole code owner could never be merged by anyone.
 #
-# Both named accounts have write access, which a code owner must have to count.
-# These lines currently resolve to the same two people as the catch-all, so
-# their present effect is documentary: they record which paths are authorities.
-# If the catch-all ever widens, they narrow again on their own.
+# @0j0bit and @sed-boi are two GitHub accounts controlled by the SAME project
+# owner. Either account may satisfy the code-owner review requirement for a
+# change it did not author -- in practice, changes proposed by the
+# mcl-release-governor App and reviewed as @0j0bit. This is account redundancy,
+# NOT independent two-person review, and nothing here claims separation of
+# duties.
+#
+# Both accounts have write access, which a code owner must have to count. The
+# path lines below name the same accounts as the catch-all, so their present
+# effect is documentary: they record which paths are authorities. If the
+# catch-all ever widens, they narrow again on their own.
 
 * @0j0bit @sed-boi
 

README.md

@@ -1,6 +1,48 @@
-# MCL Link
-
-`mcl-link` defines contact establishment, framing, sessions, addressing, quality-of-service, negotiation, and adaptation for the Machine Contact Layer.
+<p align="center">
+  <img src="https://raw.githubusercontent.com/machine-contact-layer/.github/main/profile/banner.png" alt="OJOBIT" width="100%">
+</p>
+
+<h1 align="center">MCL Link</h1>
+
+<p align="center"><strong>Keeping one contact alive — through framing, sessions, and a change of transport.</strong></p>
+
+<p align="center">
+  <a href="https://github.com/machine-contact-layer/mcl-link/actions/workflows/ci.yml"><img alt="CI" src="https://github.com/machine-contact-layer/mcl-link/actions/workflows/ci.yml/badge.svg"></a>
+  <a href="https://github.com/machine-contact-layer/mcl-link/blob/main/LICENSE"><img alt="License Apache-2.0" src="https://img.shields.io/badge/license-Apache--2.0-blue"></a>
+  <img alt="Link major 1" src="https://img.shields.io/badge/link%20major-1%20Stable-brightgreen">
+  <img alt="C99 freestanding" src="https://img.shields.io/badge/C99-freestanding-informational">
+</p>
+
+<p align="center">
+  <a href="https://github.com/machine-contact-layer/mcl-sdk"><b>Use the SDK instead</b></a> ·
+  <a href="https://github.com/machine-contact-layer/mcl-core"><b>Specifications</b></a> ·
+  <a href="https://github.com/machine-contact-layer/mcl-wire"><b>mcl-wire</b></a>
+</p>
+
+---
+
+> ### Most people should start with the SDK, not here
+>
+> This repository is a **specification**. If you are building a product, start
+> with [**mcl-sdk**](https://github.com/machine-contact-layer/mcl-sdk): its quickstart runs two machines making
+> contact, and the release ships a self-contained developer SDK — one CMake
+> project, no sibling checkout. Come back here when you need to know exactly
+> what a byte means, or when you are writing an independent implementation.
+
+## Why this exists
+
+A contact that dies when the radio changes is not a contact. MCL Link is what
+survives the change: framing, session identity, negotiation, refusal, and
+migration from one transport to another without starting over.
+
+This is the layer every binding maps onto, which is why a `HAZARD` means the
+same thing over a loudspeaker and over UDP. In one physical campaign a single logical
+contact was preserved across **104 physical-medium changes**, including 100
+alternating BLE/IP migrations.
+
+**Link major 1 is Stable.** That migration campaign carried major-0 traffic;
+Wire 1 inside Link 1 is evidenced separately, decoded over air on an embedded
+target.
 
 It is transport-profile neutral. MCL-AP, MCL-IP, MCL-BLE, MCL-UWB, and future bindings implement the same link/session contract through different physical transports.