docs: clarify manual clipboard dependencies

src/utils/clipboard.py

@@ -1,8 +1,7 @@
-import threading
 import logging
-import subprocess
 import shutil
 import sys
+import threading
 
 import pyperclip
 
@@ -10,31 +9,38 @@ logger = logging.getLogger(__name__)
 
 
 def _ensure_clipboard() -> None:
-    """Attempt to ensure a clipboard mechanism is available."""
+    """Ensure a clipboard mechanism is available or raise an informative error."""
     try:
         pyperclip.copy("")
     except pyperclip.PyperclipException as exc:
         if sys.platform.startswith("linux"):
             if shutil.which("xclip") is None and shutil.which("xsel") is None:
-                apt = shutil.which("apt-get") or shutil.which("apt")
-                if apt:
-                    try:
-                        subprocess.run(
-                            ["sudo", apt, "install", "-y", "xclip"], check=True
-                        )
-                        pyperclip.copy("")
-                        return
-                    except Exception as install_exc:  # pragma: no cover - system dep
-                        logger.warning(
-                            "Automatic xclip installation failed: %s", install_exc
-                        )
-        raise exc
+                raise pyperclip.PyperclipException(
+                    "Clipboard support requires the 'xclip' package. "
+                    "Install it with 'sudo apt install xclip' and restart SeedPass."
+                ) from exc
+        raise
 
 
-def copy_to_clipboard(text: str, timeout: int) -> None:
-    """Copy text to the clipboard and clear after timeout seconds if unchanged."""
+def copy_to_clipboard(text: str, timeout: int) -> bool:
+    """Copy text to the clipboard and clear after timeout seconds if unchanged.
+
+    Returns True if the text was successfully copied, False otherwise.
+    """
+
+    try:
+        _ensure_clipboard()
+    except pyperclip.PyperclipException as exc:
+        warning = (
+            "Clipboard unavailable: "
+            + str(exc)
+            + "\nSeedPass secret mode requires clipboard support. "
+            "Install xclip or disable secret mode to view secrets."
+        )
+        logger.warning(warning)
+        print(warning)
+        return False
 
-    _ensure_clipboard()
     pyperclip.copy(text)
 
     def clear_clipboard() -> None:
@@ -44,3 +50,4 @@ def copy_to_clipboard(text: str, timeout: int) -> None:
     timer = threading.Timer(timeout, clear_clipboard)
     timer.daemon = True
     timer.start()
+    return True