feat(frontend): implement comprehensive API Settings Management Interface

Implement a complete API Management Interface for React frontend with split-
panel layout, migrating all features from legacy JS frontend.

New Features:
- API Settings page with 5 tabs: Providers, Endpoints, Cache, Model Pools, CLI Settings
- Provider Management: CRUD operations, multi-key rotation, health checks, test connection
- Endpoint Management: CRUD operations, cache strategy configuration, enable/disable toggle
- Cache Settings: Global configuration, statistics display, clear cache functionality
- Model Pool Management: CRUD operations, auto-discovery feature, provider exclusion
- CLI Settings Management: Provider-based and Direct modes, full CRUD support
- Multi-Key Settings Modal: Manage API keys with rotation strategies and weights
- Manage Models Modal: View and manage models per provider (LLM and Embedding)
- Sync to CodexLens: Integration handler for provider configuration sync

Technical Implementation:
- Created 12 new React components in components/api-settings/
- Extended lib/api.ts with 460+ lines of API client functions
- Created hooks/useApiSettings.ts with 772 lines of TanStack Query hooks
- Added RadioGroup UI component for form selections
- Implemented unified error handling with useNotifications across all operations
- Complete i18n support (500+ keys in English and Chinese)
- Route integration (/api-settings) and sidebar navigation

Code Quality:
- All acceptance criteria from plan.json verified
- Code review passed with Gemini (all 7 IMPL tasks complete)
- Follows existing patterns: Shadcn UI, TanStack Query, react-intl, Lucide icons

ccw/src/tools/cli-executor-core.ts

@@ -345,6 +345,45 @@ import {
 const BUILTIN_CLI_TOOLS = ['gemini', 'qwen', 'codex', 'opencode', 'claude'] as const;
 type BuiltinCliTool = typeof BUILTIN_CLI_TOOLS[number];
 
+/**
+ * Transaction ID type for concurrent session disambiguation
+ * Format: ccw-tx-${conversationId}-${timestamp}
+ */
+export type TransactionId = string;
+
+/**
+ * Generate a unique transaction ID for the current execution
+ * @param conversationId - CCW conversation ID
+ * @returns Transaction ID in format: ccw-tx-${conversationId}-${uniquePart}
+ */
+export function generateTransactionId(conversationId: string): TransactionId {
+  // Use crypto.randomUUID() if available, otherwise use timestamp + random
+  const uniquePart = typeof crypto !== 'undefined' && crypto.randomUUID
+    ? crypto.randomUUID().slice(0, 8)
+    : `${Date.now()}-${Math.random().toString(36).slice(2, 9)}`;
+  return `ccw-tx-${conversationId}-${uniquePart}`;
+}
+
+/**
+ * Inject transaction ID into user prompt
+ * @param prompt - Original user prompt
+ * @param txId - Transaction ID to inject
+ * @returns Prompt with transaction ID injected at the start
+ */
+export function injectTransactionId(prompt: string, txId: TransactionId): string {
+  return `[CCW-TX-ID: ${txId}]\n\n${prompt}`;
+}
+
+/**
+ * Extract transaction ID from prompt
+ * @param prompt - Prompt that may contain transaction ID
+ * @returns Transaction ID if found, null otherwise
+ */
+export function extractTransactionId(prompt: string): TransactionId | null {
+  const match = prompt.match(/\[CCW-TX-ID:\s+([^\]]+)\]/);
+  return match ? match[1] : null;
+}
+
 // Define Zod schema for validation
 // tool accepts built-in tools or custom endpoint IDs (CLI封装)
 const ParamsSchema = z.object({
@@ -788,6 +827,17 @@ async function executeCliTool(
         timestamp: new Date().toISOString()
       });
     }
+
+    // Info message for Codex TTY limitation
+    if (tool === 'codex' && !supportsNativeResume(tool) && resumeDecision.strategy !== 'native') {
+      if (onOutput) {
+        onOutput({
+          type: 'stderr',
+          content: '[ccw] Using prompt-concat mode for Codex (Codex TTY limitation for native resume)\n',
+          timestamp: new Date().toISOString()
+        });
+      }
+    }
   }
 
   // Use configured primary model if no explicit model provided

ccw/src/tools/cli-history-store.ts

@@ -82,6 +82,7 @@ export interface NativeSessionMapping {
   native_session_id: string;   // Native UUID
   native_session_path?: string; // Native file path
   project_hash?: string;       // Project hash (Gemini/Qwen)
+  transaction_id?: string;     // Transaction ID for concurrent session disambiguation
   created_at: string;
 }
 
@@ -360,6 +361,23 @@ export class CliHistoryStore {
 
         console.log('[CLI History] Migration complete: turns table updated');
       }
+
+      // Add transaction_id column to native_session_mapping table for concurrent session disambiguation
+      const mappingInfo = this.db.prepare('PRAGMA table_info(native_session_mapping)').all() as Array<{ name: string }>;
+      const hasTransactionId = mappingInfo.some(col => col.name === 'transaction_id');
+
+      if (!hasTransactionId) {
+        console.log('[CLI History] Migrating database: adding transaction_id column to native_session_mapping...');
+        this.db.exec(`
+          ALTER TABLE native_session_mapping ADD COLUMN transaction_id TEXT;
+        `);
+        try {
+          this.db.exec(`CREATE INDEX IF NOT EXISTS idx_native_transaction_id ON native_session_mapping(transaction_id);`);
+        } catch (indexErr) {
+          console.warn('[CLI History] Transaction ID index creation warning:', (indexErr as Error).message);
+        }
+        console.log('[CLI History] Migration complete: transaction_id column added');
+      }
     } catch (err) {
       console.error('[CLI History] Migration error:', (err as Error).message);
       // Don't throw - allow the store to continue working with existing schema
@@ -926,12 +944,13 @@ export class CliHistoryStore {
    */
   saveNativeSessionMapping(mapping: NativeSessionMapping): void {
     const stmt = this.db.prepare(`
-      INSERT INTO native_session_mapping (ccw_id, tool, native_session_id, native_session_path, project_hash, created_at)
-      VALUES (@ccw_id, @tool, @native_session_id, @native_session_path, @project_hash, @created_at)
+      INSERT INTO native_session_mapping (ccw_id, tool, native_session_id, native_session_path, project_hash, transaction_id, created_at)
+      VALUES (@ccw_id, @tool, @native_session_id, @native_session_path, @project_hash, @transaction_id, @created_at)
       ON CONFLICT(ccw_id) DO UPDATE SET
         native_session_id = @native_session_id,
         native_session_path = @native_session_path,
-        project_hash = @project_hash
+        project_hash = @project_hash,
+        transaction_id = @transaction_id
     `);
 
     this.withRetry(() => stmt.run({
@@ -940,6 +959,7 @@ export class CliHistoryStore {
       native_session_id: mapping.native_session_id,
       native_session_path: mapping.native_session_path || null,
       project_hash: mapping.project_hash || null,
+      transaction_id: mapping.transaction_id || null,
       created_at: mapping.created_at || new Date().toISOString()
     }));
   }
@@ -964,6 +984,16 @@ export class CliHistoryStore {
     return row?.ccw_id || null;
   }
 
+  /**
+   * Get transaction ID by CCW ID
+   */
+  getTransactionId(ccwId: string): string | null {
+    const row = this.db.prepare(`
+      SELECT transaction_id FROM native_session_mapping WHERE ccw_id = ?
+    `).get(ccwId) as any;
+    return row?.transaction_id || null;
+  }
+
   /**
    * Get full mapping by CCW ID
    */

ccw/src/tools/native-session-discovery.ts

@@ -94,6 +94,12 @@ abstract class SessionDiscoverer {
 
     // Try to match by prompt content (fallback for parallel execution)
     const matched = this.matchSessionByPrompt(sessions, prompt);
+
+    // Warn if multiple sessions and no prompt match found (low confidence)
+    if (!matched && sessions.length > 1) {
+      console.warn(`[ccw] Session tracking: multiple candidates found (${sessions.length}), using latest session`);
+    }
+
     return matched || sessions[0]; // Fallback to latest if no match
   }
 

ccw/src/tools/resume-strategy.ts

@@ -5,6 +5,13 @@
 
 import type { ConversationTurn, ConversationRecord, NativeSessionMapping } from './cli-history-store.js';
 
+/**
+ * Emit user warning for silent fallback scenarios
+ */
+function warnUser(message: string): void {
+  console.warn(`[ccw] ${message}`);
+}
+
 // Strategy types
 export type ResumeStrategy = 'native' | 'prompt-concat' | 'hybrid';
 
@@ -78,6 +85,7 @@ export function determineResumeStrategy(options: ResumeStrategyOptions): ResumeD
   });
 
   if (crossTool) {
+    warnUser('Cross-tool resume: using prompt concatenation (different tool)');
     return buildPromptConcatDecision(resumeIds, getConversation);
   }
 
@@ -94,6 +102,7 @@ export function determineResumeStrategy(options: ResumeStrategyOptions): ResumeD
     }
 
     // No native mapping, fall back to prompt-concat
+    warnUser('No native session mapping found, using prompt concatenation');
     return buildPromptConcatDecision(resumeIds, getConversation);
   }
 
@@ -109,6 +118,7 @@ function buildPromptConcatDecision(
   getConversation: (ccwId: string) => ConversationRecord | null
 ): ResumeDecision {
   const allTurns: ConversationTurn[] = [];
+  let hasMissingConversation = false;
 
   for (const id of resumeIds) {
     const conversation = getConversation(id);
@@ -119,9 +129,16 @@ function buildPromptConcatDecision(
         _sourceId: id
       }));
       allTurns.push(...turnsWithSource as ConversationTurn[]);
+    } else {
+      hasMissingConversation = true;
     }
   }
 
+  // Warn if any conversation was not found
+  if (hasMissingConversation) {
+    warnUser('One or more resume IDs not found, using prompt concatenation (new session created)');
+  }
+
   // Sort by timestamp
   allTurns.sort((a, b) =>
     new Date(a.timestamp).getTime() - new Date(b.timestamp).getTime()