fix(ci-installer): remove dynamic path defines for ISCC

- use static relative paths in .iss for source/output

- pass only version and /O override to ISCC

- add explicit source/script path diagnostics in build.py

build.py

@@ -200,18 +200,30 @@ def build_installer():
         print("[ERROR] Install Inno Setup 6 or set ISCC_PATH environment variable.")
         sys.exit(1)
 
-    icon_abs_path = os.path.abspath(ICON_PATH)
+    project_root = os.path.abspath(".")
+    source_dir = os.path.abspath(DIST_DIR)
+    output_dir = os.path.abspath("dist")
+    iss_path = os.path.abspath(INSTALLER_SCRIPT)
+    print(f"[INFO] ISCC source dir: {source_dir}")
+    print(f"[INFO] ISCC output dir: {output_dir}")
+    print(f"[INFO] ISCC script: {iss_path}")
+    if not os.path.exists(source_dir):
+        print(f"[ERROR] Source dir does not exist: {source_dir}")
+        sys.exit(1)
+    if not os.path.exists(iss_path):
+        print(f"[ERROR] Installer script does not exist: {iss_path}")
+        sys.exit(1)
     command = [
         iscc_path,
         f"/DMyAppVersion={VERSION}",
-        f"/DMySourceDir={os.path.abspath(DIST_DIR)}",
-        f"/DMyOutputDir={os.path.abspath('dist')}",
-        os.path.abspath(INSTALLER_SCRIPT),
+        f"/O{output_dir}",
+        iss_path,
     ]
     try:
         completed = subprocess.run(
             command,
             capture_output=True,
+            cwd=project_root,
             check=False,
         )
         stdout_text = _decode_process_output(completed.stdout)