Docs carry the shape of the system, not its status

MIZAN.md's phase-numbered implementation order, PRODUCT_ARCHITECTURE's
"Deferred until Render revenue funds it" and "Shipped in", PSR_VS_EDGE's
current-state section, and the READMEs' passing-test counts were all reporting
where the work stood rather than what the system is. OWED_SURFACE keeps its
subject — surface that is specified but unbuilt — stated as the shape each unit
owes.

The channel sections follow the renamed slots: Params / ClientMessage /
ServerMessage, and Channel as the base class on both backends.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

backends/mizan-django/README.md

@@ -119,18 +119,24 @@ dedicated `mizan-allauth` repository, built on this mixin.
 
 ## Channels
 
-WebSocket-native RPC via a flag flip:
+WebSocket-native RPC via a flag flip. The message slots are named from the
+client's point of view: `ClientMessage` travels client → server,
+`ServerMessage` travels server → client. Declare only the directions the
+channel uses.
 
 ```python
 from pydantic import BaseModel
-from mizan.channels import ReactChannel
+from mizan.channels import Channel
 
 
-class ChatChannel(ReactChannel):
+class ChatChannel(Channel):
     class Params(BaseModel):
         room: str
 
-    class DjangoMessage(BaseModel):
+    class ClientMessage(BaseModel):
+        text: str
+
+    class ServerMessage(BaseModel):
         text: str
         user: str
 
@@ -139,10 +145,19 @@ class ChatChannel(ReactChannel):
 
     def group(self, params):
         return f"chat_{params.room}"
+
+    def receive(self, params, msg):
+        return self.ServerMessage(text=msg.text, user=self.user.email)
 ```
 
 Frontend gets `useChatChannel({ room })`.
 
+Server code outside a subscription broadcasts with `push()`:
+
+```python
+await ChatChannel.push(room="general", message=ChatChannel.ServerMessage(...))
+```
+
 ## Generate the frontend
 
 The codegen is the `mizan-generate` Rust binary (source at