feat: add /api/translate proxy and expose email body to plugins

lib/plugin-projection.ts

@@ -5,6 +5,40 @@
 import type { Email } from '@/lib/jmap/types';
 import type { EmailReadView } from '@/lib/plugin-types';
 
+// Resolve a message's plain-text body from its JMAP body parts. Plugins that
+// translate or scan content need the real body, not just the short `preview`
+// snippet. Prefers text/plain parts; falls back to stripped HTML, then preview.
+function plainTextFromEmail(email: Email): string {
+  const values = email.bodyValues || {};
+  const collect = (parts?: { partId: string }[]) =>
+    (parts || [])
+      .map((p) => values[p.partId]?.value)
+      .filter((v): v is string => typeof v === 'string' && v.length > 0)
+      .join('\n')
+      .trim();
+
+  const text = collect(email.textBody);
+  if (text) return text;
+
+  const html = collect(email.htmlBody);
+  if (html) {
+    return html
+      .replace(/<(script|style)[\s\S]*?<\/\1>/gi, ' ')
+      .replace(/<[^>]+>/g, ' ')
+      .replace(/&nbsp;/gi, ' ')
+      .replace(/&amp;/gi, '&')
+      .replace(/&lt;/gi, '<')
+      .replace(/&gt;/gi, '>')
+      .replace(/&#39;|&apos;/gi, "'")
+      .replace(/&quot;/gi, '"')
+      .replace(/[ \t]{2,}/g, ' ')
+      .replace(/\n{3,}/g, '\n\n')
+      .trim();
+  }
+
+  return (email.preview || '').trim();
+}
+
 export function emailToReadView(email: Email): EmailReadView {
   return {
     id: email.id,
@@ -19,6 +53,7 @@ export function emailToReadView(email: Email): EmailReadView {
     isFlagged: !!email.keywords?.['$flagged'],
     hasAttachment: email.hasAttachment,
     preview: email.preview || '',
+    text: plainTextFromEmail(email),
     keywords: Object.keys(email.keywords || {}).filter(k => email.keywords[k]),
     auth: email.authenticationResults,
   };

lib/plugin-types.ts

@@ -374,6 +374,10 @@ export interface EmailReadView {
   hasAttachment: boolean;
   preview: string;
   keywords: string[];
+  /** Full plain-text body of the message (HTML-only bodies are stripped to
+   *  text). Empty string when the host hasn't loaded the body. Same
+   *  `email:read` sensitivity as the rest of this view. */
+  text: string;
   /**
    * Parsed Authentication-Results header (SPF, DKIM, DMARC, reverse-DNS).
    * Absent on stores that didn't parse the header (e.g. bodies not yet