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.Headless.Tests/HeadlessSessionHostTests.cs

@@ -3,6 +3,7 @@ using System.Collections.Immutable;
 using System.Net;
 using System.Numerics;
 using System.Reflection;
+using System.Text.Json;
 using AcDream.Core.Net;
 using AcDream.Core.Net.Messages;
 using AcDream.Core.Physics;
@@ -61,6 +62,95 @@ public sealed class HeadlessSessionHostTests
         Assert.DoesNotContain("AcDream.App", diagnostics);
     }
 
+    /// <summary>
+    /// Campaign LA slice LA1: proves the status-event writer fires the
+    /// pinned lifecycle vocabulary — started/connected/characterList/
+    /// enteredWorld/disconnected/exited — in order, from a real
+    /// <see cref="HeadlessSessionHost"/> start+dispose cycle, and that the
+    /// roster surfaced matches <see cref="FixtureSessionOperations.GetCharacters"/>
+    /// exactly (before selection has happened — the roster is reported for
+    /// BOTH candidates, not just the selected one).
+    /// </summary>
+    [Fact]
+    public void StatusFileReceivesThePinnedLifecycleEventsInOrder()
+    {
+        string statusPath = Path.Combine(
+            Path.GetTempPath(),
+            $"acdream-headless-status-{Guid.NewGuid():N}.jsonl");
+        try
+        {
+            var operations = new FixtureSessionOperations();
+            using var diagnosticsOutput = new StringWriter();
+            using var credential = new HeadlessCredentialSecret(
+                "fixture",
+                "password");
+            using var host = new HeadlessSessionHost(
+                Descriptor(statusFile: statusPath),
+                credential,
+                new HeadlessDiagnosticWriter(diagnosticsOutput),
+                operations);
+
+            RuntimeSessionStartResult started = host.Start();
+            Assert.Equal(RuntimeSessionStartStatus.Connected, started.Status);
+            host.Dispose();
+
+            string[] lines = File.ReadAllLines(statusPath);
+            string[] eventNames = lines
+                .Select(line => JsonDocument.Parse(line)
+                    .RootElement.GetProperty("e").GetString()!)
+                .ToArray();
+            Assert.Equal(
+                [
+                    "started", "connected", "characterList", "enteredWorld",
+                    "disconnected", "exited",
+                ],
+                eventNames);
+
+            using JsonDocument characterListDoc = JsonDocument.Parse(
+                lines[Array.IndexOf(eventNames, "characterList")]);
+            JsonElement characterList = characterListDoc.RootElement;
+            Assert.Equal("account", characterList.GetProperty("accountName").GetString());
+            Assert.Equal(2, characterList.GetProperty("characters").GetArrayLength());
+
+            using JsonDocument enteredWorldDoc = JsonDocument.Parse(
+                lines[Array.IndexOf(eventNames, "enteredWorld")]);
+            Assert.Equal(
+                0x50000002u,
+                enteredWorldDoc.RootElement.GetProperty("characterId").GetUInt32());
+
+            using JsonDocument exitedDoc = JsonDocument.Parse(
+                lines[Array.IndexOf(eventNames, "exited")]);
+            Assert.Equal(0, exitedDoc.RootElement.GetProperty("code").GetInt32());
+
+            string contents = File.ReadAllText(statusPath);
+            Assert.DoesNotContain("password", contents, StringComparison.Ordinal);
+        }
+        finally
+        {
+            if (File.Exists(statusPath))
+                File.Delete(statusPath);
+        }
+    }
+
+    [Fact]
+    public void AbsentStatusFileConstructsANoOpWriter()
+    {
+        var operations = new FixtureSessionOperations();
+        using var diagnosticsOutput = new StringWriter();
+        using var credential = new HeadlessCredentialSecret("fixture", "password");
+        using var host = new HeadlessSessionHost(
+            Descriptor(),
+            credential,
+            new HeadlessDiagnosticWriter(diagnosticsOutput),
+            operations);
+
+        RuntimeSessionStartResult started = host.Start();
+
+        Assert.Equal(RuntimeSessionStartStatus.Connected, started.Status);
+        // No exception, and (implicitly) no file was ever touched — the
+        // writer is a permanent no-op with no configured path.
+    }
+
     [Fact]
     public async Task ProcessHostRunsUntilCancellationAndReturnsStableExitCode()
     {
@@ -1937,7 +2027,9 @@ public sealed class HeadlessSessionHostTests
                     _ => { },
                     () => { }),
                 (_, _, _) => { },
-                () => { }));
+                () => { },
+                _ => { },
+                _ => { }));
     }
 
     private sealed class ThrowingLiveSessionOperations : ILiveSessionOperations
@@ -1967,7 +2059,8 @@ public sealed class HeadlessSessionHostTests
         HeadlessCredentialProviderKind provider =
             HeadlessCredentialProviderKind.Environment,
         string credentialReference = "BOT_PASSWORD",
-        Dictionary<string, bool>? characterOptions = null) => new()
+        Dictionary<string, bool>? characterOptions = null,
+        string? statusFile = null) => new()
     {
         Id = "bot",
         Endpoint = new HeadlessEndpointDescriptor
@@ -1990,6 +2083,7 @@ public sealed class HeadlessSessionHostTests
             Reference = credentialReference,
         },
         CharacterOptions = characterOptions,
+        StatusFile = statusFile,
     };
 
     private static void HydrateGroundedPlayer(GameRuntime runtime)