Shorten the weak-password messaging everywhere (Ed's approved wording)

The password guidance was a wall of text. Trimmed to Ed's approved phrasing, applied
consistently across all three surfaces (status line left as-is per Ed):

- PasswordStrength.Critique is now ONE line — the rule + a concrete example to copy
  ("Use at least 8 characters — three unrelated words with a number, like
  kettle9tiger42moon, works well."), no scare prose. This flows into both change-
  password-box rejection dialogs, so those shortened automatically.
- Startup warning (MaybeWarnWeakPassword): "RemSound has increased its security level,
  so this profile's password must be strengthened to meet the new password rules.
  Until it is, no audio will pass." + the one-line rule + how to change it.
- Send/Receive-tick gate (EnsureStreamingPassword): same "increased its security
  level ... strengthened before audio can flow" opener + the concise rule.

Gate 71/71 + 7 relay tests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/RemSound.App/MainForm.cs

@@ -1684,15 +1684,13 @@ public sealed partial class MainForm : Form
         if (IsDisposed || CuePlayer.GloballyMuted) return; // never on a --silent/automated launch
         if (!WeakPasswordBlocksAudio(currentProfilePassword, currentAudioKey is not null)) return;
         if (!IsSendEnabled && !IsReceiveEnabled) return;   // not trying to stream → nothing blocked yet
-        var advice = PasswordStrength.Critique(currentProfilePassword) ?? "";
         ForegroundDialog.Show(owner => MessageBox.Show(owner,
-            "The password on this profile — the one that protects your audio — is too easy to guess, so "
-                + "from this version RemSound won't stream with it. Until it's changed, the people you "
-                + "connect to will hear nothing.\n\n"
-                + advice + "\n\n"
-                + "To fix it: open the File menu and choose “Change this profile's password”, then set "
-                + "the SAME new password on every machine you connect with.",
-            "RemSound — password too weak to stream",
+            "RemSound has increased its security level, so this profile's password must be strengthened "
+                + "to meet the new password rules. Until it is, no audio will pass.\n\n"
+                + "Use at least 8 characters — three unrelated words with a number, like kettle9tiger42moon, works well.\n\n"
+                + "To change it: open the File menu and choose “Change this profile's password”. Use the "
+                + "same new password on every machine you connect with.",
+            "RemSound — password needs strengthening",
             MessageBoxButtons.OK, MessageBoxIcon.Warning));
     }
 
@@ -8429,9 +8427,10 @@ public sealed partial class MainForm : Form
             // it — a bare dialog would read as a bug to someone whose password worked yesterday.
             var page = new TaskDialogPage
             {
-                Caption = "Password needs strengthening",
-                Heading = "Your profile password is too easy to guess",
-                Text = $"From this version, audio won't flow until the password is stronger. {weakAdvice}",
+                Caption = "RemSound — password needs strengthening",
+                Heading = "Your password must be strengthened",
+                Text = "RemSound has increased its security level, so this profile's password must be "
+                     + $"strengthened before audio can flow. {weakAdvice}",
                 Icon = TaskDialogIcon.Warning,
                 Buttons = { TaskDialogButton.OK },
                 DefaultButton = TaskDialogButton.OK,

src/RemSound.Core/PasswordStrength.cs

@@ -28,20 +28,14 @@ public static class PasswordStrength
     public static string? Critique(string password)
     {
         if (string.IsNullOrEmpty(password)) return null;
+        // Kept short on purpose (Ed, 2026-07-27): one line — the rule and a concrete example to copy
+        // the shape of. The surrounding dialogs add the "why" and the "how to change it".
         if (password.Length < MinLength)
-        {
-            return $"This password is too short to protect your audio — anyone who records your stream can try millions of guesses against it. "
-                 + $"Use at least {MinLength} characters; longer is stronger. Three unrelated words with a number — like kettle9tiger42moon — "
-                 + "is easy to type and remember, and very hard to guess. Remember: every machine you connect with must be given the same new password.";
-        }
+            return $"Use at least {MinLength} characters — three unrelated words with a number, like kettle9tiger42moon, works well.";
         foreach (var common in CommonPasswords)
         {
             if (string.Equals(password, common, StringComparison.OrdinalIgnoreCase))
-            {
-                return "That password is one of the most commonly guessed passwords in the world, so it offers almost no protection. "
-                     + "Pick something personal and longer — three unrelated words with a number, like kettle9tiger42moon, works well. "
-                     + "Remember: every machine you connect with must be given the same new password.";
-            }
+                return $"That's one of the most common passwords in the world. Use at least {MinLength} characters — three unrelated words with a number, like kettle9tiger42moon, works well.";
         }
         return null;
     }