style: apply cargo fmt across the crate (A20)

The repo never enforced rustfmt, so formatting had drifted broadly. This is a
single mechanical `cargo fmt` pass over the whole crate (no behavioral change;
lib suite green, 493 passed). Going forward fmt should be enforced (planned CI
fmt --check step). Part of the 0.6.1 hygiene pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/presence.rs

@@ -36,8 +36,11 @@ pub enum PresenceMode {
 
 impl PresenceMode {
     /// All postures, default first — the option list for the Settings/home picker.
-    pub const ALL: [PresenceMode; 3] =
-        [PresenceMode::Normal, PresenceMode::Invisible, PresenceMode::Discoverable];
+    pub const ALL: [PresenceMode; 3] = [
+        PresenceMode::Normal,
+        PresenceMode::Invisible,
+        PresenceMode::Discoverable,
+    ];
 
     /// Whether this posture publishes to discovery (the only mode that does).
     pub fn publishes_to_discovery(self) -> bool {
@@ -193,7 +196,11 @@ mod tests {
         assert!(!should_answer(&friend, &friends, PresenceMode::Invisible));
         // Stranger is NEVER answered, in any mode.
         assert!(!should_answer(&stranger, &friends, PresenceMode::Normal));
-        assert!(!should_answer(&stranger, &friends, PresenceMode::Discoverable));
+        assert!(!should_answer(
+            &stranger,
+            &friends,
+            PresenceMode::Discoverable
+        ));
         assert!(!should_answer(&stranger, &friends, PresenceMode::Invisible));
     }
 
@@ -214,7 +221,10 @@ mod tests {
             ControlMsg::Ping,
             ControlMsg::Pong { room: None },
             ControlMsg::Pong {
-                room: Some(RoomPresence { name: "HangOut".into(), ticket: "abc".into() }),
+                room: Some(RoomPresence {
+                    name: "HangOut".into(),
+                    ticket: "abc".into(),
+                }),
             },
         ];
         for msg in cases {
@@ -245,19 +255,37 @@ mod tests {
         );
         // Valid ticket -> InRoom with a sanitized name.
         let t = valid_ticket(friend);
-        let got = interpret_pong(&ControlMsg::Pong {
-            room: Some(RoomPresence { name: "HangOut".into(), ticket: t.clone() }),
-        }, friend);
-        assert_eq!(got, Some(FriendPresence::InRoom { name: "HangOut".into(), ticket: t }));
+        let got = interpret_pong(
+            &ControlMsg::Pong {
+                room: Some(RoomPresence {
+                    name: "HangOut".into(),
+                    ticket: t.clone(),
+                }),
+            },
+            friend,
+        );
+        assert_eq!(
+            got,
+            Some(FriendPresence::InRoom {
+                name: "HangOut".into(),
+                ticket: t
+            })
+        );
     }
 
     #[test]
     fn interpret_pong_downgrades_a_garbage_ticket_to_online() {
         // A friend reporting a room with an unparseable ticket is treated as just
         // Online — no dead/hostile Join button is surfaced.
-        let got = interpret_pong(&ControlMsg::Pong {
-            room: Some(RoomPresence { name: "Trap".into(), ticket: "not-a-ticket".into() }),
-        }, id());
+        let got = interpret_pong(
+            &ControlMsg::Pong {
+                room: Some(RoomPresence {
+                    name: "Trap".into(),
+                    ticket: "not-a-ticket".into(),
+                }),
+            },
+            id(),
+        );
         assert_eq!(got, Some(FriendPresence::Online));
     }
 
@@ -266,9 +294,15 @@ mod tests {
         let friend = id();
         let attacker = id();
         let t = valid_ticket(attacker);
-        let got = interpret_pong(&ControlMsg::Pong {
-            room: Some(RoomPresence { name: "Redirect".into(), ticket: t }),
-        }, friend);
+        let got = interpret_pong(
+            &ControlMsg::Pong {
+                room: Some(RoomPresence {
+                    name: "Redirect".into(),
+                    ticket: t,
+                }),
+            },
+            friend,
+        );
         assert_eq!(got, Some(FriendPresence::Online));
     }
 
@@ -287,10 +321,18 @@ mod tests {
         let t = valid_ticket(friend);
         assert_eq!(
             presence_from_probe(Some((
-                &ControlMsg::Pong { room: Some(RoomPresence { name: "Den".into(), ticket: t.clone() }) },
+                &ControlMsg::Pong {
+                    room: Some(RoomPresence {
+                        name: "Den".into(),
+                        ticket: t.clone()
+                    })
+                },
                 friend,
             ))),
-            FriendPresence::InRoom { name: "Den".into(), ticket: t }
+            FriendPresence::InRoom {
+                name: "Den".into(),
+                ticket: t
+            }
         );
         // A non-reply (a stray Ping) is not a presence -> Offline, never a false Online.
         assert_eq!(
@@ -304,9 +346,15 @@ mod tests {
         // Control/bidi characters in a peer-supplied name are stripped.
         let friend = id();
         let t = valid_ticket(friend);
-        let got = interpret_pong(&ControlMsg::Pong {
-            room: Some(RoomPresence { name: "Hang\u{202e}Out\u{0007}".into(), ticket: t.clone() }),
-        }, friend);
+        let got = interpret_pong(
+            &ControlMsg::Pong {
+                room: Some(RoomPresence {
+                    name: "Hang\u{202e}Out\u{0007}".into(),
+                    ticket: t.clone(),
+                }),
+            },
+            friend,
+        );
         match got {
             Some(FriendPresence::InRoom { name, .. }) => {
                 assert!(!name.contains('\u{202e}'), "bidi override must be stripped");