3.B：vendor opencore-amr + AMRCodec Swift wrapper，打通 AMR↔WAV 编解码

为支撑 H5 的 prepareaudio / mediaTypeAudio 录音上传 + 远端语音播放
（docs/H5-Native-Contract.md §3.1 ［4］［5］ + §3.2 ［9］）接入 AMR-NB
编解码能力。AMR-NB 是跨端（iOS / Android / 旧版本客户端）契约硬约束，
不可换 AAC / Opus。

## 接入路径

直接 vendor daoqi msext 现成的 fat .a（已上线多年），不打 xcframework /
不重编源码：
- Vendor/OpenCoreAMR/v0.1.x/libopencore-amrnb.a：daoqi 同款 5-slice fat
  库（含 2026-06-20 lipo -segalign 8 修过的对齐版本）
- Vendor/OpenCoreAMR/v0.1.x/{interf_dec,interf_enc}.h：amrnb 公开头
- Vendor/OpenCoreAMR/README.md：来源、版本、修复历史、为何不打 xcframework
- ylgamehall/Source/Audio/AMRFileCodec/{amrFileCodec.h,amrFileCodec.mm}：
  daoqi 同款 wrapper（文件级 WAV↔AMR 处理）
- ylgamehall/Source/Audio/AMRCodec.swift：Swift 薄 wrapper（wavToAmr /
  amrToWav 两个纯函数 + AMRCodec.Error）

理由见 Vendor/OpenCoreAMR/README.md「为何不打 xcframework / 不重编源码」
一节，本质是 opencore-amr 整个 iOS 生态没有"现代主流"分发形态，社区无
官方 SPM / xcframework 维护，强行打反而引入新风险。

## 关键技术点：extern "C" 修复 ObjC++ name mangling

amrFileCodec.h 在原项目里没有 extern "C" 包裹函数声明，daoqi 能跑是
因为调用方 VoiceConverter.mm 也是 ObjC++，双方按相同 C++ name mangling
链接能对上。

新外壳从 Swift 通过 bridging-header 调用，Swift 按 C 函数解析，期望符号
_EncodeWAVEFileToAMRFile / _DecodeWAVEFileToWAVEFile（C 链接）；但
.mm 编译时默认 C++ name mangling，符号变成 __Z25Encode...，导致链接器
报 Undefined symbol。

修复：在 amrFileCodec.h 的函数声明外加 #ifdef __cplusplus / extern "C"
包裹。这是标准 C/C++ 头文件兼容写法，对 daoqi 老路径无影响（ObjC++
调用方仍能链接 C-linkage 函数）。

## .gitignore：白名单 Vendor 下的 .a

发现历史遗留问题：原 .gitignore *.a 通配规则把 libWeChatSDK.a 也排除
了，意味着别人 clone 此仓库后链接失败。本次顺带修复：

  !Vendor/**/*.a

让 Vendor 下的 .a 显式纳入跟踪。本提交同时把 libWeChatSDK.a（历史
缺失）+ libopencore-amrnb.a（本次新增）一并加入 git 跟踪。

## 工程改动

pbxproj 改动由用户在 Xcode UI 完成（4 项 Build Settings：Add .a 到
Frameworks group / Header Search Paths +2 / Library Search Paths +1；
EXCLUDED_ARCHS arm64-simulator 因真机调试场景暂未配，需要时再加）。

## 验证

BuildProject 通过，0 错误，符号链接正确。XcodeRefreshCodeIssuesInFile
对 AMRCodec.swift 0 诊断。

ylgamehall.xcodeproj/project.pbxproj

@@ -19,6 +19,7 @@
 		1A2955002FEA48CD009E703E /* libWeChatSDK.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 1A2954F92FEA0B59009E703E /* libWeChatSDK.a */; };
 		1A2955012FEA48D9009E703E /* libz.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = 1A2954FA2FEA0BA8009E703E /* libz.tbd */; };
 		1A2955022FEA48E4009E703E /* libsqlite3.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = 1A2954FB2FEA0BB9009E703E /* libsqlite3.tbd */; };
+		1A2955102FEAF514009E703E /* libopencore-amrnb.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 1A29550F2FEAF514009E703E /* libopencore-amrnb.a */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -32,6 +33,7 @@
 		1A2954FB2FEA0BB9009E703E /* libsqlite3.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = libsqlite3.tbd; path = usr/lib/libsqlite3.tbd; sourceTree = SDKROOT; };
 		1A2954FC2FEA0BCE009E703E /* Security.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Security.framework; path = System/Library/Frameworks/Security.framework; sourceTree = SDKROOT; };
 		1A2954FE2FEA0BD8009E703E /* CFNetwork.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CFNetwork.framework; path = System/Library/Frameworks/CFNetwork.framework; sourceTree = SDKROOT; };
+		1A29550F2FEAF514009E703E /* libopencore-amrnb.a */ = {isa = PBXFileReference; lastKnownFileType = archive.ar; name = "libopencore-amrnb.a"; path = "Vendor/OpenCoreAMR/v0.1.x/libopencore-amrnb.a"; sourceTree = "<group>"; };
 		1A714BD22FE8047A00913338 /* ylgamehall.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = ylgamehall.app; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
 
@@ -70,6 +72,7 @@
 				1A2954EF2FE9BA6E009E703E /* CoreTelephony.framework in Frameworks */,
 				1A2954E32FE99C53009E703E /* AMapFoundationKit.framework in Frameworks */,
 				1A2954DA2FE97D61009E703E /* Qiniu in Frameworks */,
+				1A2955102FEAF514009E703E /* libopencore-amrnb.a in Frameworks */,
 				1A2954ED2FE9BA49009E703E /* SystemConfiguration.framework in Frameworks */,
 				1A2954FD2FEA0BCE009E703E /* Security.framework in Frameworks */,
 				1A2954F12FE9BA7C009E703E /* ExternalAccessory.framework in Frameworks */,
@@ -82,6 +85,7 @@
 		1A2954DB2FE99B2F009E703E /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				1A29550F2FEAF514009E703E /* libopencore-amrnb.a */,
 				1A2954FE2FEA0BD8009E703E /* CFNetwork.framework */,
 				1A2954FC2FEA0BCE009E703E /* Security.framework */,
 				1A2954FB2FEA0BB9009E703E /* libsqlite3.tbd */,
@@ -212,7 +216,11 @@
 					"$(PROJECT_DIR)/Vendor/AMap",
 				);
 				GENERATE_INFOPLIST_FILE = YES;
-				HEADER_SEARCH_PATHS = "$(PROJECT_DIR)/Vendor/WechatSDK/v1.8.2";
+				HEADER_SEARCH_PATHS = (
+					"$(PROJECT_DIR)/Vendor/WechatSDK/v1.8.2",
+					"$(PROJECT_DIR)/Vendor/OpenCoreAMR/v0.1.x",
+					"$(PROJECT_DIR)/ylgamehall/Source/Audio/AMRFileCodec",
+				);
 				INFOPLIST_FILE = ylgamehall/Info.plist;
 				INFOPLIST_KEY_UIApplicationSupportsIndirectInputEvents = YES;
 				INFOPLIST_KEY_UILaunchStoryboardName = LaunchScreen;
@@ -227,6 +235,7 @@
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(PROJECT_DIR)/Vendor/WechatSDK/v1.8.2",
+					"$(PROJECT_DIR)/Vendor/OpenCoreAMR/v0.1.x",
 				);
 				MARKETING_VERSION = 1.0;
 				OTHER_LDFLAGS = "-ObjC";
@@ -256,7 +265,11 @@
 					"$(PROJECT_DIR)/Vendor/AMap",
 				);
 				GENERATE_INFOPLIST_FILE = YES;
-				HEADER_SEARCH_PATHS = "$(PROJECT_DIR)/Vendor/WechatSDK/v1.8.2";
+				HEADER_SEARCH_PATHS = (
+					"$(PROJECT_DIR)/Vendor/WechatSDK/v1.8.2",
+					"$(PROJECT_DIR)/Vendor/OpenCoreAMR/v0.1.x",
+					"$(PROJECT_DIR)/ylgamehall/Source/Audio/AMRFileCodec",
+				);
 				INFOPLIST_FILE = ylgamehall/Info.plist;
 				INFOPLIST_KEY_UIApplicationSupportsIndirectInputEvents = YES;
 				INFOPLIST_KEY_UILaunchStoryboardName = LaunchScreen;
@@ -271,6 +284,7 @@
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(PROJECT_DIR)/Vendor/WechatSDK/v1.8.2",
+					"$(PROJECT_DIR)/Vendor/OpenCoreAMR/v0.1.x",
 				);
 				MARKETING_VERSION = 1.0;
 				OTHER_LDFLAGS = "-ObjC";