Refactor signer implementation to use p8k package

- Replaced all instances of p256k1signer with the new p8k.Signer across various modules, including event creation, policy handling, and database interactions.
- Updated related test cases and benchmarks to ensure compatibility with the new signer interface.
- Bumped version to v0.25.0 to reflect these significant changes and improvements in cryptographic operations.

go.sum

@@ -24,6 +24,8 @@ github.com/dgryski/go-farm v0.0.0-20240924180020-3414d57e47da h1:aIftn67I1fkbMa5
 github.com/dgryski/go-farm v0.0.0-20240924180020-3414d57e47da/go.mod h1:SqUrOPUnsFjfmXRMNPybcSiG0BgUW2AuFH8PAnS2iTw=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
+github.com/ebitengine/purego v0.9.1 h1:a/k2f2HQU3Pi399RPW1MOaZyhKJL9w/xFpKAg4q1s0A=
+github.com/ebitengine/purego v0.9.1/go.mod h1:iIjxzd6CiRiOG0UyXP+V1+jWqUXVjPKLAI0mRfJZTmQ=
 github.com/felixge/fgprof v0.9.3/go.mod h1:RdbpDgzqYVh/T9fPELJyV7EYJuHB55UTEULNun8eiPw=
 github.com/felixge/fgprof v0.9.5 h1:8+vR6yu2vvSKn08urWyEuxx75NWPEvybbkBirEpsbVY=
 github.com/felixge/fgprof v0.9.5/go.mod h1:yKl+ERSa++RYOs32d8K6WEXCB4uXdLls4ZaZPpayhMM=
@@ -144,5 +146,5 @@ lol.mleku.dev v1.0.5 h1:irwfwz+Scv74G/2OXmv05YFKOzUNOVZ735EAkYgjgM8=
 lol.mleku.dev v1.0.5/go.mod h1:JlsqP0CZDLKRyd85XGcy79+ydSRqmFkrPzYFMYxQ+zs=
 lukechampine.com/frand v1.5.1 h1:fg0eRtdmGFIxhP5zQJzM1lFDbD6CUfu/f+7WgAZd5/w=
 lukechampine.com/frand v1.5.1/go.mod h1:4VstaWc2plN4Mjr10chUD46RAVGWhpkZ5Nja8+Azp0Q=
-p256k1.mleku.dev v1.0.3 h1:2SBEH9XhNAotO1Ik8ejODjChTqc06Z/6ncQhrYkAdRA=
-p256k1.mleku.dev v1.0.3/go.mod h1:cWkZlx6Tu7CTmIxonFbdjhdNfkY3VbjjY5TFEILiTnY=
+p8k.mleku.dev v1.0.0 h1:4I5kH2EAyXDnb8rCGQoKLkf0v1tSfSWRJAbvjmOIK8w=
+p8k.mleku.dev v1.0.0/go.mod h1:6q4pvm9hBK7dXiF6W2iEc1mboWAHJcce/65YDinf6uw=