docs: Campaign LA — pinned launch-contract schema COMMITTED into plan LA1

The LA3 Opus review process note was right: the contract both sides
implement lived only in orchestrator prompts, which is exactly the drift
mode the pin exists to prevent (and it produced the paths-key CRITICAL).
The schema, field rules, probe-mode discriminator, and status vocabulary
are now a binding plan section; amendments change this text first,
implementations second. Ledger: LA3 fix round dispatched.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/AcDream.Runtime.Tests/Session/RuntimeLiveEntitySessionControllerTests.cs

@@ -1049,7 +1049,9 @@ public sealed class RuntimeLiveEntitySessionControllerTests
                     _ => { },
                     () => { }),
                 (_, _, _) => { },
-                () => { }),
+                () => { },
+                _ => { },
+                _ => { }),
             options);
         LiveSessionStartResult startResult = live.Start(options);
         Assert.Equal(LiveSessionStartStatus.Connected, startResult.Status);