fix: auto-reply not triggering when source_prefix is empty (#880)

* fix: auto-reply not triggering when source_prefix is empty (#459)

- Empty source_prefix now matches all senders (was short-circuiting as falsy)
- Support regex matching with /pattern/ syntax in source_prefix
- Backward compatible: plain strings still use startsWith
- Use E2E_TEST_MODE switch to skip cloudflare:email import in tests
- Track reply() calls in E2E mock for testability

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: update auto-reply UI labels for regex support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: update changelogs for auto-reply fix and regex feature

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: upgrade version to v1.5.0

- Update version number to 1.5.0 in all package.json files and constants.ts
- Split CHANGELOG: v1.4.0 entries finalized, new v1.5.0(main) section with auto-reply changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: add error logging for invalid regex in auto-reply source_prefix

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* refactor: address CodeRabbit review suggestions

- Use const object instead of let for mock state tracking
- Add log when auto-reply subject/message falls back to defaults

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: add source_prefix regex syntax to auto-reply docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/views/index/AutoReply.vue

@@ -21,7 +21,8 @@ const { t } = useI18n({
         en: {
             success: 'Success',
             settings: 'Settings',
-            sourcePrefix: 'Source Mail Prefix',
+            sourcePrefix: 'Sender Filter',
+            sourcePrefixPlaceholder: 'Empty=all, prefix match, or /regex/',
             name: 'Name',
             enableAutoReply: 'Enable Auto Reply',
             subject: 'Subject',
@@ -31,7 +32,8 @@ const { t } = useI18n({
         zh: {
             success: '成功',
             settings: '设置',
-            sourcePrefix: '来源邮件前缀',
+            sourcePrefix: '发件人过滤',
+            sourcePrefixPlaceholder: '留空=全部匹配，前缀匹配，或 /正则/',
             name: '名称',
             enableAutoReply: '启用自动回复',
             subject: '主题',
@@ -93,7 +95,8 @@ onMounted(async () => {
                     <n-input :disabled="!enableAutoReply" v-model:value="name" />
                 </n-form-item>
                 <n-form-item :label="t('sourcePrefix')" label-placement="left">
-                    <n-input :disabled="!enableAutoReply" v-model:value="sourcePrefix" />
+                    <n-input :disabled="!enableAutoReply" v-model:value="sourcePrefix"
+                        :placeholder="t('sourcePrefixPlaceholder')" />
                 </n-form-item>
                 <n-form-item :label="t('subject')" label-placement="left">
                     <n-input :disabled="!enableAutoReply" v-model:value="subject" />