Feat/dkim module (#257)

This Cosmos SDK module mimics DKIM (DomainKeys Identified Mail)
functionality by securely storing information found in email headers,
specifically DKIM public keys and hashes associated with specific
domains. This allows verification of email authenticity on the
blockchain. The module also implements a method to calculate Poseidon
hashes of public keys, providing a secure and efficient way to verify
the authenticity of a public key that signed an email.

---------

Signed-off-by: Kehinde Faleye <Kenny.fale.kf@gmail.com>
Co-authored-by: Ash <96692350+ash-burnt@users.noreply.github.com>
Co-authored-by: 2xburnt <169301814+2xburnt@users.noreply.github.com>
Co-authored-by: Ash <ash@burnt.com>
Co-authored-by: Eduardo Diaz <eduardo.j.diaz.rodriguez@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Kushal7788 <kushshah777888@gmail.com>
Co-authored-by: Kushal <41788348+Kushal7788@users.noreply.github.com>
Co-authored-by: Eduardo Díaz <edjroz@users.noreply.github.com>

Author: 6 people

.coveragerc

@@ -24,5 +24,3 @@ github.com/burnt-labs/xion/indexer/client/cli/indexer.go:.*ReIndex
 # Wasm keeper metadata retrieval (requires full keeper setup for success path)
 # Error path is tested; success path needs integration test with real keeper
 github.com/burnt-labs/xion/app/keepers/wasm_keeper.go:.*GetXionContractMetadata
-
-github.com/burnt-labs/xion/app/v25_upgrade

.husky/hooks/pre-commit

@@ -1,2 +1,2 @@
 #!/bin/sh
-make format && make lint && make test-cover
+make format && make lint && make test-cover