Define canonical Persims repository layout

README.md

@@ -1,3 +1,11 @@
-# persims
+# Persims
 
-Persimmons — permissions put plainly
+Canonical source for Persimmons.
+
+- Current website: repository root
+- Chromium extension: `extension/`
+- Shared/runtime source: `backend/`
+- Pre-cutover snapshot: `old/`
+
+Public site: https://persimmons.app
+Platform identity/API: https://teahub.xyz