Release Mail Tools 0.1.0

public/docs/ARCHITECTURE.md

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+# Architecture
+
+The React shell lazy-loads one workbench. `core/mime.ts` turns bounded source
+text into immutable-looking header and MIME-part records; parsing never creates
+DOM. Transfer decoding consumes a global byte budget. Diagnostics, comparison,
+canonicalization and redaction are separate pure modules.
+
+Only the selected HTML text is passed through DOMPurify. It is then embedded in
+an iframe without sandbox capabilities and with an inner policy that denies all
+connections and active content. Attachment downloads are explicit Blob URLs
+with sanitized filenames. The service worker caches only same-origin app files.