Remove local replace; resolve contract_lock_sdk from private module.

Co-authored-by: Cursor <cursoragent@cursor.com>

go.mod

@@ -8,5 +8,3 @@ require (
 )
 
 require github.com/tjfoc/gmsm v1.4.1 // indirect
-
-replace git.sxidc.com/student-physical-examination/contract_lock_sdk => ../contract_lock_sdk

go.sum

@@ -1,4 +1,6 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+git.sxidc.com/student-physical-examination/contract_lock_sdk v0.0.0-20250705084345-056db4cca05c h1:xqCaiYR4CxMer9GQiswo5AAxcM0m5+ujDdOD0F/tcSs=
+git.sxidc.com/student-physical-examination/contract_lock_sdk v0.0.0-20250705084345-056db4cca05c/go.mod h1:pW4sBcSKNzKwIbN/9U6FfmSPHAWfXKsrre6nTeNlpfE=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=