fix(tray): drop the conflicting-host warning — the tray is the wrong place for it

The tray led its tooltip with "⚠ conflicting host: Sunshine" and (on Linux)
went NeedsAttention for a Sunshine that was merely *installed* — never
started, never listening, harmless. An always-on warning over a dormant
package is a false alarm on every poll, and the tray is the wrong surface
for a one-shot install-time observation anyway.

Removes the `conflicts` field from the tray's `Summary`, the tooltip prefix,
`has_conflicts()`, and the ksni attention branch that fed on it. The host
still detects and reports conflicts where that belongs — the startup
`punktfunk::detect` warning, the `detect-conflicts` subcommand, and the
`/api/v1/local/summary` field, which the tray must (and does, per the new
test) keep tolerating on the wire.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

crates/punktfunk-tray/src/linux.rs

@@ -53,7 +53,7 @@ impl ksni::Tray for HostTray {
     fn status(&self) -> ksni::Status {
         match &self.status {
             TrayStatus::Error(_) => ksni::Status::NeedsAttention,
-            s if s.pairing_attention() || s.has_conflicts() => ksni::Status::NeedsAttention,
+            s if s.pairing_attention() => ksni::Status::NeedsAttention,
             _ => ksni::Status::Active,
         }
     }