feature / refactor : 채점 시스템 SSE → WebSocket 기반으로 전환 (#98)

* feat : WebSocket 관련 클래스, 메서드, DTO 추가

* refactor : WebSocket으로 채점 시스템 전환

Author: thezz9

src/main/java/org/ezcode/codetest/application/submission/dto/event/SubmissionErrorEvent.java

@@ -0,0 +1,23 @@
+package org.ezcode.codetest.application.submission.dto.event;
+
+import org.ezcode.codetest.domain.submission.exception.SubmissionException;
+import org.ezcode.codetest.domain.submission.exception.code.SubmissionExceptionCode;
+
+public record SubmissionErrorEvent(
+
+    String sessionKey,
+
+    SubmissionExceptionCode code
+
+) {
+    public SubmissionErrorEvent(String sessionKey, Throwable t) {
+        this(sessionKey, resolveCode(t));
+    }
+
+    private static SubmissionExceptionCode  resolveCode(Throwable t) {
+        if (t instanceof SubmissionException se) {
+            return (SubmissionExceptionCode) se.getResponseCode();
+        }
+        return SubmissionExceptionCode.UNKNOWN_ERROR;
+    }
+}

src/main/java/org/ezcode/codetest/application/submission/dto/event/SubmissionJudgingFinishedEvent.java

@@ -0,0 +1,12 @@
+package org.ezcode.codetest.application.submission.dto.event;
+
+import org.ezcode.codetest.application.submission.dto.event.payload.SubmissionFinalResultPayload;
+
+public record SubmissionJudgingFinishedEvent(
+
+    String sessionKey,
+
+    SubmissionFinalResultPayload payload
+
+) {
+}

src/main/java/org/ezcode/codetest/application/submission/dto/event/TestcaseEvaluatedEvent.java

@@ -0,0 +1,18 @@
+package org.ezcode.codetest.application.submission.dto.event;
+
+import org.ezcode.codetest.application.submission.dto.event.payload.TestcaseResultPayload;
+
+public record TestcaseEvaluatedEvent(
+
+    String sessionKey,
+
+    TestcaseResultPayload payload
+
+) {
+    public static TestcaseEvaluatedEvent of(String sessionKey, TestcaseResultPayload payload) {
+        return new TestcaseEvaluatedEvent(
+            sessionKey,
+            payload
+        );
+    }
+}

src/main/java/org/ezcode/codetest/application/submission/dto/event/TestcaseListInitializedEvent.java

@@ -0,0 +1,17 @@
+package org.ezcode.codetest.application.submission.dto.event;
+
+import java.util.List;
+
+import org.ezcode.codetest.application.submission.dto.event.payload.InitTestcaseListPayload;
+
+public record TestcaseListInitializedEvent(
+
+    String sessionKey,
+
+    List<InitTestcaseListPayload> payload
+
+) {
+    public static TestcaseListInitializedEvent from(String sessionKey, List<InitTestcaseListPayload> payload) {
+        return new TestcaseListInitializedEvent(sessionKey, payload);
+    }
+}

src/main/java/org/ezcode/codetest/application/submission/dto/event/payload/InitTestcaseListPayload.java

@@ -0,0 +1,33 @@
+package org.ezcode.codetest.application.submission.dto.event.payload;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+import org.ezcode.codetest.domain.problem.model.ProblemInfo;
+import org.ezcode.codetest.domain.problem.model.entity.Testcase;
+
+public record InitTestcaseListPayload(
+
+    int seqId,
+
+    String input,
+
+    String expectedOutput,
+
+    String status
+
+) {
+    public static List<InitTestcaseListPayload> from(ProblemInfo info) {
+        return IntStream.rangeClosed(1, info.getTestcaseCount())
+            .mapToObj(seq -> {
+                Testcase tc = info.testcaseList().get(seq - 1);
+                return new InitTestcaseListPayload(
+                    seq,
+                    tc.getInput(),
+                    tc.getOutput(),
+                    "채점 중"
+                );
+            })
+            .toList();
+    }
+}

src/main/java/org/ezcode/codetest/application/submission/dto/event/payload/SubmissionFinalResultPayload.java

@@ -0,0 +1,22 @@
+package org.ezcode.codetest.application.submission.dto.event.payload;
+
+import lombok.Getter;
+
+@Getter
+public class SubmissionFinalResultPayload {
+
+    private final int totalCount;
+
+    private final int passedCount;
+
+    private final boolean isCorrect;
+
+    private final String message;
+
+    public SubmissionFinalResultPayload(int totalCount, int passedCount, String message) {
+        this.totalCount = totalCount;
+        this.passedCount = passedCount;
+        this.isCorrect = totalCount == passedCount;
+        this.message = message;
+    }
+}

src/main/java/org/ezcode/codetest/application/submission/dto/event/payload/TestcaseResultPayload.java

@@ -0,0 +1,30 @@
+package org.ezcode.codetest.application.submission.dto.event.payload;
+
+import org.ezcode.codetest.application.submission.model.JudgeResult;
+import org.ezcode.codetest.domain.submission.dto.AnswerEvaluation;
+
+public record TestcaseResultPayload(
+
+    int seqId,
+
+    boolean isPassed,
+
+    String actualOutput,
+
+    long executionTime,
+
+    long memoryUsage,
+
+    String message
+
+) {
+    public static TestcaseResultPayload fromEvaluation(int seqId, JudgeResult result, AnswerEvaluation evaluation) {
+        return new TestcaseResultPayload(
+            seqId,
+            evaluation.isPassed(),
+            result.actualOutput(),
+            result.executionTime(),
+            result.memoryUsage(),
+            result.message());
+    }
+}

src/main/java/org/ezcode/codetest/application/submission/dto/response/submission/FinalResultResponse.java

@@ -22,7 +22,7 @@ public record SubmissionDetailResponse(
     String message,
 
     @Schema(description = "실행 시간 (s)", example = "0.129")
-    Double executionTime,
+    Long executionTime,
 
     @Schema(description = "메모리 사용량 (KB)", example = "12196")
     Long memoryUsage,