feat(launcher): Campaign LA LA3 — AcDream.Launcher.Core profile store, composer, supervisor, status tailer

New AcDream.Launcher.Core (BCL-only, ProjectReference: AcDream.Platform
ONLY) plus tests/AcDream.Launcher.Core.Tests, both registered in
AcDream.slnx. This is the file-contract orchestrator core the Avalonia
launcher (LA4) will bind to — the game solution (Core/Runtime/App/
Headless) stays entirely out of this dependency graph, so the launcher
can never accidentally grow a game-protocol coupling.

- Profiles/: LauncherProfileStore owns launcher-profiles.json (spec §5
  schema: version 1, servers[]/accounts[]/characters[]), strict
  camelCase System.Text.Json (UnmappedMemberHandling.Disallow), typed
  CRUD (add/edit/remove server; add/edit/remove account; edit character
  settings), and MergeRoster (fold a reported roster into an account's
  characters[] while preserving user-owned launchMode/plugins/
  loginCommands, adding new rows with default guiSelect, and retaining
  rows absent from the roster — they may be pending-delete). 0600 on
  Linux via File.SetUnixFileMode after save.
- Launching/: SessionConfigComposer builds the pinned session-config
  contract (Headless K1 shape + plugins/loginCommands/
  loginCommandDelayMs/statusFile) from a profile character + install
  record — character selector omitted entirely for guiSelect, policy
  {id:"idle"} only for headless, credential always standardInput/
  session. Passwords never enter this document (proven by a dedicated
  test). LauncherProcessSupervisor spawns a host, feeds the password to
  stdin then closes it, and exposes Starting/Running/Exited lifecycle;
  Stop calls CloseMainWindow falling back to Kill after a timeout, both
  reachable through an injectable ILauncherChildProcess/factory seam so
  the state machine is unit-testable without real OS process timing.
- Status/: StatusEventParser decodes the v1 status.jsonl vocabulary
  (started/connected/characterList/enteredWorld/pluginLoaded/
  pluginFailed/disconnected/exited); an unrecognized "e" or a malformed
  line degrades to a typed Unknown event rather than throwing.
  StatusFileTailer incrementally reads new lines, tolerating a
  not-yet-existing file and a partial trailing line (only advances its
  read position past confirmed '\n' boundaries; a truncated tail is
  simply re-read next poll, never parsed early).
- Integrity/: streaming SHA-256 + hex verify for later pak/download
  checks (LA9/LA10).

Tests: 71 passed (profile CRUD + roster-merge matrix + strict-schema
rejection; composer golden-shape tests for gui/guiSelect/headless +
password-absence; supervisor tests against both an injected fake child
(state-machine determinism) and a real spawned `dotnet --version`
child (genuine cross-platform stdin/exit-code proof); tailer tests
incl. partial-line and not-yet-existing-file; SHA-256 tests). Verified
green on Windows (Release) and native WSL/Linux (Release) — the Linux
0600 test executes its real assertion body under WSL rather than
early-returning.

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

src/AcDream.Launcher.Core/Profiles/LaunchMode.cs

@@ -0,0 +1,35 @@
+namespace AcDream.Launcher.Core.Profiles;
+
+/// <summary>
+/// Per-character launch behaviour (Campaign LA spec §5). Stored on each
+/// <see cref="CharacterProfile"/> and read by
+/// <see cref="AcDream.Launcher.Core.Launching.SessionConfigComposer"/> to
+/// decide the shape of the composed session-config document.
+///
+/// <para>
+/// Serialized as camelCase text (<c>"gui"</c>/<c>"guiSelect"</c>/
+/// <c>"headless"</c>) via the explicit
+/// <c>new JsonStringEnumConverter(JsonNamingPolicy.CamelCase, ...)</c>
+/// registered in <see cref="LauncherProfileStore"/>'s serializer options
+/// — deliberately NOT a per-type <c>[JsonConverter]</c> attribute, which
+/// uses exact member-name casing (<c>"Gui"</c>) regardless of the
+/// ambient <c>PropertyNamingPolicy</c>.
+/// </para>
+/// </summary>
+public enum LaunchMode
+{
+    /// <summary>Launch the graphical client straight into the world as
+    /// this character.</summary>
+    Gui,
+
+    /// <summary>Launch the graphical client but stop at the retail
+    /// character-select screen — no character selector is sent. This is
+    /// the default for a character that has never had its launch mode set
+    /// explicitly.</summary>
+    GuiSelect,
+
+    /// <summary>Launch the no-window host running the <c>idle</c> bot
+    /// policy (enter world, run plugins/login commands, stay until
+    /// stopped).</summary>
+    Headless,
+}