refactor: massive rename dap -> dat

- Renamed packages io.shinhanlife.dap to io.shinhanlife.dat
- Renamed modules dap-was-* and dap-gateway to dat-was-* and dat-gateway
- Renamed classes DapGateway* to DatGateway*
- Updated all references

dat-was-sys/build.gradle

@@ -0,0 +1,9 @@
+plugins {
+    // Spring Boot 3.5.11 version is managed by the root build.gradle.
+    id 'org.springframework.boot'
+}
+
+dependencies {
+    // Shared MCP, Glow integration, validation, logging, Lombok and MapStruct configuration.
+    implementation project(':dat-was-lib')
+}