Refine version assignment and clean up build script

Update version retrieval logic and remove debug prints.

Author: TylerS1066

build.gradle.kts

@@ -17,7 +17,7 @@ dependencies {
 }
 
 group = "io.github.apdevteam"
-version = System.getenv("RELEASE_VERSION")
+version = System.getenv("RELEASE_VERSION")?.takeIf { it.isNotBlank() }
     ?: System.getenv("GITHUB_SHA")?.take(7)
     ?: runCatching {
         val sha = ProcessBuilder("git", "rev-parse", "--short", "HEAD")
@@ -29,10 +29,6 @@ version = System.getenv("RELEASE_VERSION")
 description = "ModMail"
 java.toolchain.languageVersion = JavaLanguageVersion.of(25)
 
-println(">>> Resolved version: $version")
-println(">>> RELEASE_VERSION env: ${System.getenv("RELEASE_VERSION")}")
-println(">>> GITHUB_SHA env: ${System.getenv("GITHUB_SHA")}")
-
 tasks.jar {
     manifest {
         attributes(