chore(session): satisfy the master gates on the v1-to-v2 branch

`session-format-v1-to-v2` takes the `0.1.2-rc.1` root version that master
requires, and `defineReleasedPayloadDisposition` drops the `@param` tag for a
parameter it no longer has.

packages/session/session-format-v0-to-v1/src/dispositions.ts

@@ -11,7 +11,6 @@ export interface ReleasedV0PayloadDisposition {
  * @param required - members that must be present.
  * @param optional - additional admitted members.
  * @param opaque - members retained as lossless JSON without nested semantic inspection.
- * @param extensionArms - nested discriminant paths that admit owner-defined variants.
  * @returns the detached frozen disposition.
  */
 export function defineReleasedPayloadDisposition(

packages/session/session-format-v1-to-v2/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@deepseek-ai/dsh-session-format-v1-to-v2",
   "description": "Frozen released-v1 Session codec and assistant-stream migration to v2",
-  "version": "0.1.2-alpha.5",
+  "version": "0.1.2-rc.1",
   "publishConfig": {
     "access": "public"
   },