feat(browser): 增加 Phase 6B mock response 能力

在现有拦截规则之上补齐 fulfill 动作，支持最小状态码、响应头和文本响应体。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/mcp/ccs-browser-server.cjs

@@ -477,7 +477,22 @@ function getTools() {
           pageId: { type: 'string' },
           urlIncludes: { type: 'string' },
           method: { type: 'string' },
-          action: { type: 'string', enum: ['continue', 'fail'] },
+          action: { type: 'string', enum: ['continue', 'fail', 'fulfill'] },
+          statusCode: { type: 'integer', minimum: 100, maximum: 599 },
+          headers: {
+            type: 'array',
+            items: {
+              type: 'object',
+              properties: {
+                name: { type: 'string' },
+                value: { type: 'string' },
+              },
+              required: ['name', 'value'],
+              additionalProperties: false,
+            },
+          },
+          body: { type: 'string' },
+          contentType: { type: 'string' },
         },
         required: ['action'],
         additionalProperties: false,
@@ -801,12 +816,56 @@ function parseOptionalPageId(toolArgs) {
 }
 
 function parseInterceptAction(value) {
-  if (value !== 'continue' && value !== 'fail') {
-    throw new Error('action must be one of: continue, fail');
+  if (value !== 'continue' && value !== 'fail' && value !== 'fulfill') {
+    throw new Error('action must be one of: continue, fail, fulfill');
   }
   return value;
 }
 
+function parseOptionalStatusCode(value) {
+  if (value === undefined) {
+    return 200;
+  }
+  if (!Number.isInteger(value) || value < 100 || value > 599) {
+    throw new Error('statusCode must be an integer between 100 and 599');
+  }
+  return value;
+}
+
+function parseOptionalHeaders(value, contentType) {
+  const headers = [];
+  if (Array.isArray(value)) {
+    for (const entry of value) {
+      if (!entry || typeof entry !== 'object') {
+        throw new Error('headers entries must be objects with name and value');
+      }
+      const name = requireNonEmptyString(entry.name, 'headers.name');
+      const headerValue = String(entry.value ?? '');
+      headers.push({ name, value: headerValue });
+    }
+  } else if (value !== undefined) {
+    throw new Error('headers must be an array');
+  }
+  if (contentType && !headers.some((header) => header.name.toLowerCase() === 'content-type')) {
+    headers.push({ name: 'Content-Type', value: contentType });
+  }
+  return headers;
+}
+
+function parseOptionalBody(value) {
+  if (value === undefined) {
+    return '';
+  }
+  if (typeof value !== 'string') {
+    throw new Error('body must be a string');
+  }
+  return value;
+}
+
+function encodeFulfillBody(body) {
+  return Buffer.from(body, 'utf8').toString('base64');
+}
+
 function parseOptionalMethod(value) {
   if (value === undefined) {
     return '';
@@ -862,6 +921,8 @@ function formatInterceptRules(rules) {
         `urlIncludes: ${rule.urlIncludes || '<any>'}`,
         `method: ${rule.method || '<any>'}`,
         `action: ${rule.action}`,
+        `statusCode: ${rule.action === 'fulfill' ? rule.statusCode : 'n/a'}`,
+        `contentType: ${rule.action === 'fulfill' ? rule.contentType || '<none>' : 'n/a'}`,
       ].join('\n')
     )
     .join('\n---\n');
@@ -881,6 +942,7 @@ function formatRecentRequests(entries) {
         `resourceType: ${entry.resourceType || ''}`,
         `matchedRuleId: ${entry.matchedRuleId || 'none'}`,
         `action: ${entry.action}`,
+        `statusCode: ${entry.action === 'fulfill' ? entry.statusCode : 'n/a'}`,
       ].join('\n')
     )
     .join('\n---\n');
@@ -2574,6 +2636,19 @@ async function ensureInterceptSession(page) {
             params: { requestId: paused.requestId, errorReason: FETCH_FAIL_ERROR_REASON },
           })
         );
+      } else if (action === 'fulfill') {
+        ws.send(
+          JSON.stringify({
+            id: ++requestCounter,
+            method: 'Fetch.fulfillRequest',
+            params: {
+              requestId: paused.requestId,
+              responseCode: matchedRule.statusCode,
+              responseHeaders: matchedRule.headers,
+              body: encodeFulfillBody(matchedRule.body),
+            },
+          })
+        );
       } else {
         ws.send(
           JSON.stringify({
@@ -2591,6 +2666,7 @@ async function ensureInterceptSession(page) {
         resourceType: String(paused.resourceType || ''),
         matchedRuleId: matchedRule ? matchedRule.ruleId : '',
         action,
+        statusCode: action === 'fulfill' ? matchedRule.statusCode : 0,
       });
     })();
     activityChain = activityChain.catch(() => {}).then(() => activity).catch(() => {});
@@ -2696,10 +2772,15 @@ async function handleAddInterceptRule(toolArgs) {
   }
   const urlIncludes = parseOptionalUrlIncludes(toolArgs.urlIncludes);
   const method = parseOptionalMethod(toolArgs.method);
+  const action = parseInterceptAction(toolArgs.action);
   if (!urlIncludes && !method) {
     throw new Error('urlIncludes or method is required');
   }
-  const action = parseInterceptAction(toolArgs.action);
+  const statusCode = parseOptionalStatusCode(toolArgs.statusCode);
+  const contentType =
+    toolArgs.contentType === undefined ? '' : requireNonEmptyString(toolArgs.contentType, 'contentType');
+  const body = parseOptionalBody(toolArgs.body);
+  const headers = parseOptionalHeaders(toolArgs.headers, contentType);
   const rule = {
     ruleId: createInterceptRuleId(),
     pageId: page.id,
@@ -2707,6 +2788,10 @@ async function handleAddInterceptRule(toolArgs) {
     urlIncludes,
     method,
     action,
+    statusCode: action === 'fulfill' ? statusCode : 0,
+    contentType: action === 'fulfill' ? contentType : '',
+    headers: action === 'fulfill' ? headers : [],
+    body: action === 'fulfill' ? body : '',
     createdAt: new Date().toISOString(),
   };
   interceptRules.push(rule);