feat: Initial clean release of CHM

readme/dev/spec/server_sharing_e2ee.md

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+# Sharing a notebook with E2EE enabled
+
+- When sharing the notebook, a key (NOTEBOOK_KEY) is automatically generated and encrypted with the sender master password.
+	- That key ID is then associated with the notebook
+- When adding a recipient, the key is decrypted using the sender master password, and reencrypted using the recipient public key
+	- That encrypted key is then attached to the share_user object (the invitation)
+- When the recipient receives the invitation, the key is retrieved from it, then decrypted using the private key, and reencrypted using the recipient master password.
+
+Once the key exchange is done, each user has their own copy of NOTEBOOK_KEY encrypted with their own master password. Public/Private Keys are only used to transfer NOTEBOOK_KEY.
+
+Whenever any item within the notebook is encrypted, it is done with NOTEBOOK_KEY.
+
+# Migrations
+
+Enabling migration to a new public key algorithm can be done by:
+1. Registering a new public key algorithm. This involves:
+	1. Adding a new item to the `PublicKeyAlgorithm` `enum` and
+	2. Updating the `PublicKeyCryptoProvider` for each platform.
+2. Adding the new `PublicKeyAlgorithm` enum item to the `ppkMigrations` array in `ppk.ts`.