chore(test): 初始化回归测试仓（新增 .gitignore，TestsOverview.md 改为 README.md）

把 Test/ 纳入 https://git.gvsds.com/GVSDS/Viper_RegressionTesting 。

1) 新增 .gitignore —— 只保留测试源码，剔除全部构建产物：
   目录   **/output*/（output / output_opt / output_orig / output_verify / output_dbg）、
          **/temp*/（temp / temp_opt）、**/.tpv_build/
   二进制 *.exe *.obj *.o *.out *.a *.lib *.dll
   中间物 *.ll *.vpi *.pyi *.deps.txt *.deps.json *.doc.json *_sha1_map.txt
          _pyi_cache_v1.pkl _pyi_cache_v1.sig.json _shared_sym.json _phase1_manifest.json
   其它   build_all.txt（构建日志）、*.log、__pycache__/、*.bak、IDE 目录
   保留   App/*.vp、project.json / project_opt.json / project.vpj、README.md、两个 .py
   实测 `git add -A --dry-run`：196 个文件，无任何构建产物混入。

2) TestsOverview.md → README.md（作为仓库首页文档）。

3) SequentialRegressionTest.py：7 处 TestsOverview.md 引用同步改为 README.md
   （文档串、OVERVIEW 路径、read_test_order 文档与报错文案、argparse description、
   启动横幅）；同时修正入口路径 PROJECTRANS —— 旧值 <root>/Projectrans.py 已不存在，
   改为 <root>/TransPyC/Projectrans.py（与 regression_test.py:45-48 记录一致），
   否则本脚本会以 "can't open file" 全量失败。
   regression_test.py 无需改动：它按目录扫描 project.json 找项目，不引用该文档。

DefaultArgTest/App/main.vp

@@ -0,0 +1,70 @@
+import t
+import stdio
+import testcheck
+import remote
+import vrandom
+
+
+# 同模块：单个尾随默认值
+def local_one(x: int, cap: t.CSizeT = 4096) -> t.CSizeT:
+    return cap
+
+
+# 同模块：多个尾随默认值
+def local_quad(a: int, b: int = 10, c: int = 20, d: int = 30) -> int:
+    return a + b * 100 + c * 10000 + d * 1000000
+
+
+def main() -> t.CInt:
+    testcheck.begin("DefaultArgTest: default / named / out-of-order arguments")
+
+    # ① 同模块默认值
+    testcheck.section("same-module defaults")
+    r1: t.CSizeT = local_one(1)
+    testcheck.check(r1 == 4096, "local_one(1) cap = 4096", "local_one(1) cap != 4096")
+    r2: int = local_quad(1)
+    testcheck.check(r2 == 30201001, "local_quad(1) = 30201001", "local_quad(1) != 30201001")
+
+    # ② 跨模块默认值
+    testcheck.section("cross-module defaults")
+    r3: t.CSizeT = remote.one(1)
+    testcheck.check(r3 == 4096, "remote.one(1) cap = 4096", "remote.one(1) cap != 4096")
+    r4: t.CSizeT = remote.write(1, 2, False)
+    testcheck.check(r4 == 4096, "remote.write(1,2,False) cap = 4096", "remote.write(1,2,False) cap != 4096")
+
+    # ③ 显式覆盖默认值
+    testcheck.section("explicit override")
+    r5: t.CSizeT = remote.one(1, 8)
+    testcheck.check(r5 == 8, "remote.one(1,8) cap = 8", "remote.one(1,8) cap != 8")
+
+    # ④ 命名 / 乱序传参
+    testcheck.section("named / out-of-order arguments")
+    r6: t.CSizeT = remote.one(cap = 8, x = 1)
+    testcheck.check(r6 == 8, "remote.one(cap = 8, x = 1) = 8", "remote.one(cap = 8, x = 1) != 8")
+    r7: t.CSizeT = remote.one(x = 1, cap = 8)
+    testcheck.check(r7 == 8, "remote.one(x = 1, cap = 8) = 8", "remote.one(x = 1, cap = 8) != 8")
+    r8: t.CSizeT = remote.one(x = 1)
+    testcheck.check(r8 == 4096, "remote.one(x = 1) cap = 4096", "remote.one(x = 1) cap != 4096")
+    r9: int = remote.many(z = 3, x = 1, y = 2)
+    testcheck.check(r9 == 9, "remote.many(z = 3, x = 1, y = 2) = 9", "remote.many(z = 3, x = 1, y = 2) != 9")
+
+    # ⑤ 多个尾随默认值只给前几个
+    testcheck.section("partial trailing defaults")
+    r10: int = local_quad(1, 2)
+    testcheck.check(r10 == 30200201, "local_quad(1,2) = 30200201", "local_quad(1,2) != 30200201")
+    r11: int = remote.quad(1, 2)
+    testcheck.check(r11 == 30200201, "remote.quad(1,2) = 30200201", "remote.quad(1,2) != 30200201")
+    r12: int = local_quad(1, 2, 3)
+    testcheck.check(r12 == 30030201, "local_quad(1,2,3) = 30030201", "local_quad(1,2,3) != 30030201")
+    r13: int = remote.quad(1, 2, 3)
+    testcheck.check(r13 == 30030201, "remote.quad(1,2,3) = 30030201", "remote.quad(1,2,3) != 30030201")
+    r14: int = remote.quad(1)
+    testcheck.check(r14 == 30201001, "remote.quad(1) = 30201001", "remote.quad(1) != 30201001")
+
+    # ⑥ include 模块（顶层 .vp）默认值：vrandom.randrange(start, stop, step = 1)
+    # stop-start==1 ⇒ width==1 ⇒ 结果恒为 start；step 未填充时会退化为 0/垃圾
+    testcheck.section("include-module defaults")
+    r15: t.CInt = vrandom.randrange(5, 6)
+    testcheck.check(r15 == 5, "vrandom.randrange(5,6) = 5 (step default)", "vrandom.randrange(5,6) != 5")
+
+    return testcheck.end()

DefaultArgTest/App/remote.vp

@@ -0,0 +1,21 @@
+import t
+
+
+# 跨模块：单个尾随默认值（对照 includes/json/__writer.vp 的 write 形态）
+def one(x: int, cap: t.CSizeT = 4096) -> t.CSizeT:
+    return cap
+
+
+# 跨模块：4 参、最后一个有默认值（与 json.write(pool, val, pretty, cap=4096) 同形）
+def write(a: int, b: int, pretty: bool, cap: t.CSizeT = 4096) -> t.CSizeT:
+    return cap
+
+
+# 跨模块：多个尾随默认值
+def quad(a: int, b: int = 10, c: int = 20, d: int = 30) -> int:
+    return a + b * 100 + c * 10000 + d * 1000000
+
+
+# 跨模块：乱序/命名传参（wiki 04-functions.md 的 add 形态）
+def many(x: int, y: int, z: int = 1) -> int:
+    return (x + y) * z

DefaultArgTest/project.json

@@ -0,0 +1,40 @@
+{
+    "$schema": "https://raw.githubusercontent.com/TermiNexus/TransPyC/main/schemas/project-schema.json",
+    "name": "DefaultArgTest",
+    "version": "1.0.0",
+    "source_dir": "./App",
+    "build_dir": "./.tpv_build",
+    "compiler": {
+        "cmd": "llc",
+        "flags": [
+            "-filetype=obj",
+            "-relocation-model=pic"
+        ]
+    },
+    "linker": {
+        "cmd": "clang++",
+        "flags": [
+            "-Wl,--allow-multiple-definition",
+            "-lmsvcrt",
+            "-lucrt",
+            "-lpthread",
+            "-lmingwex",
+            "-lkernel32",
+            "-luser32"
+        ],
+        "output": "DefaultArgTest.exe"
+    },
+    "includes": [
+        "../../includes"
+    ],
+    "target": {
+        "triple": "x86_64-pc-windows-gnu",
+        "datalayout": "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+    },
+    "options": {
+        "slice_level": 3,
+        "sha1_slice_level": 1,
+        "target": "llvm",
+        "strict_mode": true
+    }
+}