diff --git a/src/main/java/com/label/common/context/CompanyContext.java b/src/main/java/com/label/common/context/CompanyContext.java
new file mode 100644
index 0000000..1606633
--- /dev/null
+++ b/src/main/java/com/label/common/context/CompanyContext.java
@@ -0,0 +1,21 @@
+package com.label.common.context;
+
+public class CompanyContext {
+    private static final ThreadLocal<Long> COMPANY_ID = new ThreadLocal<>();
+
+    public static void set(Long companyId) {
+        COMPANY_ID.set(companyId);
+    }
+
+    public static Long get() {
+        return COMPANY_ID.get();
+    }
+
+    public static void clear() {
+        COMPANY_ID.remove();  // Use remove() not set(null) to prevent memory leaks
+    }
+
+    private CompanyContext() {  // Prevent instantiation
+        throw new UnsupportedOperationException("Utility class");
+    }
+}
diff --git a/src/main/java/com/label/common/exception/BusinessException.java b/src/main/java/com/label/common/exception/BusinessException.java
new file mode 100644
index 0000000..1e7aede
--- /dev/null
+++ b/src/main/java/com/label/common/exception/BusinessException.java
@@ -0,0 +1,22 @@
+package com.label.common.exception;
+
+import lombok.Getter;
+import org.springframework.http.HttpStatus;
+
+@Getter
+public class BusinessException extends RuntimeException {
+    private final String code;
+    private final HttpStatus httpStatus;
+
+    public BusinessException(String code, String message) {
+        super(message);
+        this.code = code;
+        this.httpStatus = HttpStatus.BAD_REQUEST;
+    }
+
+    public BusinessException(String code, String message, HttpStatus httpStatus) {
+        super(message);
+        this.code = code;
+        this.httpStatus = httpStatus;
+    }
+}
diff --git a/src/main/java/com/label/common/exception/GlobalExceptionHandler.java b/src/main/java/com/label/common/exception/GlobalExceptionHandler.java
new file mode 100644
index 0000000..327e4e4
--- /dev/null
+++ b/src/main/java/com/label/common/exception/GlobalExceptionHandler.java
@@ -0,0 +1,28 @@
+package com.label.common.exception;
+
+import com.label.common.result.Result;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@Slf4j
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(BusinessException.class)
+    public ResponseEntity<Result<?>> handleBusinessException(BusinessException e) {
+        log.warn("业务异常: code={}, message={}", e.getCode(), e.getMessage());
+        return ResponseEntity
+            .status(e.getHttpStatus())
+            .body(Result.failure(e.getCode(), e.getMessage()));
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<Result<?>> handleException(Exception e) {
+        log.error("系统异常", e);
+        return ResponseEntity
+            .internalServerError()
+            .body(Result.failure("INTERNAL_ERROR", "系统内部错误"));
+    }
+}
diff --git a/src/main/java/com/label/common/statemachine/DatasetStatus.java b/src/main/java/com/label/common/statemachine/DatasetStatus.java
new file mode 100644
index 0000000..753d508
--- /dev/null
+++ b/src/main/java/com/label/common/statemachine/DatasetStatus.java
@@ -0,0 +1,13 @@
+package com.label.common.statemachine;
+
+import java.util.Map;
+import java.util.Set;
+
+public enum DatasetStatus {
+    PENDING_REVIEW, APPROVED, REJECTED;
+
+    public static final Map<DatasetStatus, Set<DatasetStatus>> TRANSITIONS = Map.of(
+        PENDING_REVIEW, Set.of(APPROVED, REJECTED)
+        // APPROVED/REJECTED: terminal states
+    );
+}
diff --git a/src/main/java/com/label/common/statemachine/SourceStatus.java b/src/main/java/com/label/common/statemachine/SourceStatus.java
new file mode 100644
index 0000000..324d673
--- /dev/null
+++ b/src/main/java/com/label/common/statemachine/SourceStatus.java
@@ -0,0 +1,15 @@
+package com.label.common.statemachine;
+
+import java.util.Map;
+import java.util.Set;
+
+public enum SourceStatus {
+    PENDING, PREPROCESSING, EXTRACTING, QA_REVIEW, APPROVED;
+
+    public static final Map<SourceStatus, Set<SourceStatus>> TRANSITIONS = Map.of(
+        PENDING,       Set.of(EXTRACTING, PREPROCESSING),
+        PREPROCESSING, Set.of(PENDING),
+        EXTRACTING,    Set.of(QA_REVIEW),
+        QA_REVIEW,     Set.of(APPROVED)
+    );
+}
diff --git a/src/main/java/com/label/common/statemachine/TaskStatus.java b/src/main/java/com/label/common/statemachine/TaskStatus.java
new file mode 100644
index 0000000..ccca0aa
--- /dev/null
+++ b/src/main/java/com/label/common/statemachine/TaskStatus.java
@@ -0,0 +1,16 @@
+package com.label.common.statemachine;
+
+import java.util.Map;
+import java.util.Set;
+
+public enum TaskStatus {
+    UNCLAIMED, IN_PROGRESS, SUBMITTED, APPROVED, REJECTED;
+
+    public static final Map<TaskStatus, Set<TaskStatus>> TRANSITIONS = Map.of(
+        UNCLAIMED,   Set.of(IN_PROGRESS),
+        IN_PROGRESS, Set.of(SUBMITTED, UNCLAIMED, IN_PROGRESS),  // IN_PROGRESS->IN_PROGRESS for ADMIN reassign
+        SUBMITTED,   Set.of(APPROVED, REJECTED),
+        REJECTED,    Set.of(IN_PROGRESS)
+        // APPROVED: terminal state, no outgoing transitions
+    );
+}
diff --git a/src/main/java/com/label/common/statemachine/VideoJobStatus.java b/src/main/java/com/label/common/statemachine/VideoJobStatus.java
new file mode 100644
index 0000000..0af2c9d
--- /dev/null
+++ b/src/main/java/com/label/common/statemachine/VideoJobStatus.java
@@ -0,0 +1,20 @@
+package com.label.common.statemachine;
+
+import java.util.Map;
+import java.util.Set;
+
+public enum VideoJobStatus {
+    PENDING, RUNNING, SUCCESS, FAILED, RETRYING;
+
+    /**
+     * Automatic state machine transitions.
+     * Note: FAILED → PENDING is a manual ADMIN operation, handled separately in VideoProcessService.reset().
+     */
+    public static final Map<VideoJobStatus, Set<VideoJobStatus>> TRANSITIONS = Map.of(
+        PENDING,   Set.of(RUNNING),
+        RUNNING,   Set.of(SUCCESS, FAILED, RETRYING),
+        RETRYING,  Set.of(RUNNING, FAILED)
+        // SUCCESS: terminal state
+        // FAILED → PENDING: manual ADMIN reset, NOT in this automatic transitions map
+    );
+}