Harden Yomitan settings open flow for external profile mode

- Return status from `openYomitanSettings` and show user-facing warning when external read-only profile mode blocks settings
- Thread `yomitanSession` through settings runtime/opener deps so settings window uses the active session
- Expand tests for session forwarding and external profile path propagation
- Move AniList setup/token/CLI docs into the AniList section in configuration docs

src/main/runtime/yomitan-settings-opener.ts

@@ -1,5 +1,6 @@
 type YomitanExtensionLike = unknown;
 type BrowserWindowLike = unknown;
+type SessionLike = unknown;
 
 export function createOpenYomitanSettingsHandler(deps: {
   ensureYomitanExtensionLoaded: () => Promise<YomitanExtensionLike | null>;
@@ -7,10 +8,12 @@ export function createOpenYomitanSettingsHandler(deps: {
     yomitanExt: YomitanExtensionLike;
     getExistingWindow: () => BrowserWindowLike | null;
     setWindow: (window: BrowserWindowLike | null) => void;
+    yomitanSession?: SessionLike | null;
     onWindowClosed?: () => void;
   }) => void;
   getExistingWindow: () => BrowserWindowLike | null;
   setWindow: (window: BrowserWindowLike | null) => void;
+  getYomitanSession?: () => SessionLike | null;
   logWarn: (message: string) => void;
   logError: (message: string, error: unknown) => void;
 }) {
@@ -25,6 +28,7 @@ export function createOpenYomitanSettingsHandler(deps: {
         yomitanExt: extension,
         getExistingWindow: deps.getExistingWindow,
         setWindow: deps.setWindow,
+        yomitanSession: deps.getYomitanSession?.() ?? null,
       });
     })().catch((error) => {
       deps.logError('Failed to open Yomitan settings window.', error);