cli: Word the case error for every profile

The mixed-case message said either case "recovers the same wallet", but
`_parse` shows it for every profile, including shares and application
prefixes with no wallet. Say that both cases decode to the same data.

Claude-Session: https://claude.ai/code/session_015CuLXqAvAovfoVcUmmogwa

Author: claude

src/codex32/_cli_input.py

@@ -689,7 +689,7 @@ def allowed(candidate: CorrectionCandidate) -> bool:
 
 
 _FRIENDLY_SET_ERRORS: dict[type[Exception], str] = {
-    InvalidCase: "A codex32 string is all uppercase or all lowercase; either case recovers the same wallet.",
+    InvalidCase: "A codex32 string is all uppercase or all lowercase; both cases decode to the same data.",
     InvalidChecksum: "The checksum does not match.",
     MismatchedProfile: "These strings are for different applications.",
     MismatchedThreshold: "These strings require different numbers of shares.",

tests/test_cli.py

@@ -377,7 +377,7 @@ def answer(prompt: str) -> str:
     assert prompts == ["Enter a codex32 string:\n> "] * 2
     assert rejected not in captured.out
     assert (
-        "Rejected: A codex32 string is all uppercase or all lowercase; either case recovers the same wallet.\n\n"
+        "Rejected: A codex32 string is all uppercase or all lowercase; both cases decode to the same data.\n\n"
     ) in captured.err
     assert captured.err.endswith("\n\n")