Harden Yomitan read-only logging and extract overlay options

- Redact skipped Yomitan write log values (paths to basename, titles hidden)
- Extract overlay BrowserWindow option builder for direct unit testing
- Document and test `externalProfilePath` tilde (`~`) home expansion

src/main/runtime/yomitan-read-only-log.test.ts

@@ -0,0 +1,24 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { formatSkippedYomitanWriteAction } from './yomitan-read-only-log';
+
+test('formatSkippedYomitanWriteAction redacts full filesystem paths to basenames', () => {
+  assert.equal(
+    formatSkippedYomitanWriteAction('importYomitanDictionary', '/tmp/private/merged.zip'),
+    'importYomitanDictionary(merged.zip)',
+  );
+});
+
+test('formatSkippedYomitanWriteAction redacts dictionary titles', () => {
+  assert.equal(
+    formatSkippedYomitanWriteAction('deleteYomitanDictionary', 'SubMiner Character Dictionary'),
+    'deleteYomitanDictionary(<redacted>)',
+  );
+});
+
+test('formatSkippedYomitanWriteAction falls back when value is blank', () => {
+  assert.equal(
+    formatSkippedYomitanWriteAction('upsertYomitanDictionarySettings', '   '),
+    'upsertYomitanDictionarySettings(<redacted>)',
+  );
+});