Move the ntfy alert sink to Settings, shared by all alert rules

Alert rules no longer carry their own ntfy topic/server; Settings now
holds one process-wide ntfy sink (with its own "send test notification"),
and the Alerts panel is left to just define rule conditions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

src/alerts.rs

@@ -25,7 +25,6 @@ pub struct AlertRule {
     pub name: String,
     pub enabled: bool,
     pub condition: AlertCondition,
-    pub sink: AlertSink,
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
@@ -54,17 +53,6 @@ pub enum AlertCondition {
     },
 }
 
-/// Modeled as an enum (rather than bare fields on `AlertRule`) so more sink kinds can be added later without reshaping it.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
-#[serde(tag = "kind", rename_all = "lowercase")]
-pub enum AlertSink {
-    Ntfy {
-        topic: String,
-        /// Defaults to `https://ntfy.sh` when absent.
-        server: Option<String>,
-    },
-}
-
 #[derive(Debug)]
 pub enum AlertError {
     NotFound,
@@ -107,9 +95,8 @@ impl Settings {
         name: String,
         enabled: bool,
         condition: AlertCondition,
-        sink: AlertSink,
     ) -> Result<AlertRule, AlertError> {
-        let rule = AlertRule { id: generate_alert_rule_id(&name), name, enabled, condition, sink };
+        let rule = AlertRule { id: generate_alert_rule_id(&name), name, enabled, condition };
         self.alert_rules.push(rule.clone());
         self.save(settings_path)?;
         Ok(rule)
@@ -122,7 +109,6 @@ impl Settings {
         name: String,
         enabled: bool,
         condition: AlertCondition,
-        sink: AlertSink,
     ) -> Result<AlertRule, AlertError> {
         let rule = self
             .alert_rules
@@ -132,7 +118,6 @@ impl Settings {
         rule.name = name;
         rule.enabled = enabled;
         rule.condition = condition;
-        rule.sink = sink;
         let updated = rule.clone();
         self.save(settings_path)?;
         Ok(updated)
@@ -322,15 +307,16 @@ fn evaluate_condition(
     }
 }
 
-/// Errors are only logged (no retry queue); spawned off the ingest hot path so a slow/unreachable sink never blocks ingestion.
-pub async fn deliver_for_rule(rule: AlertRule, message: String) {
-    match rule.sink {
-        AlertSink::Ntfy { topic, server } => {
-            let server = server.unwrap_or_else(|| "https://ntfy.sh".to_string());
-            if let Err(err) = deliver_ntfy(&server, &topic, &message).await {
-                eprintln!("warning: failed to deliver alert '{}' via ntfy: {err}", rule.name);
-            }
-        }
+/// Delivers to the single, process-wide ntfy sink configured in Settings. Errors are only logged
+/// (no retry queue); spawned off the ingest hot path so a slow/unreachable sink never blocks ingestion.
+/// A silently no-op'd delivery (no topic configured) is expected — a rule can be defined before the sink is.
+pub async fn deliver_for_rule(rule_name: String, message: String, topic: Option<String>, server: Option<String>) {
+    let Some(topic) = topic else {
+        return;
+    };
+    let server = server.unwrap_or_else(|| "https://ntfy.sh".to_string());
+    if let Err(err) = deliver_ntfy(&server, &topic, &message).await {
+        eprintln!("warning: failed to deliver alert '{rule_name}' via ntfy: {err}");
     }
 }
 
@@ -364,7 +350,6 @@ mod tests {
             name: "test rule".to_string(),
             enabled: true,
             condition: AlertCondition::Immediate { query: query.to_string() },
-            sink: AlertSink::Ntfy { topic: "alerts".to_string(), server: None },
         }
     }
 
@@ -380,7 +365,6 @@ mod tests {
                 "spike".to_string(),
                 true,
                 AlertCondition::Immediate { query: r#"regex("error")"#.to_string() },
-                AlertSink::Ntfy { topic: "alerts".to_string(), server: None },
             )
             .unwrap();
         assert_eq!(settings.alert_rules.len(), 1);
@@ -395,7 +379,6 @@ mod tests {
                 "renamed".to_string(),
                 false,
                 AlertCondition::Immediate { query: r#"regex("warn")"#.to_string() },
-                AlertSink::Ntfy { topic: "other".to_string(), server: Some("https://example.com".to_string()) },
             )
             .unwrap();
         assert_eq!(updated.id, created.id);
@@ -420,7 +403,6 @@ mod tests {
             "x".to_string(),
             true,
             AlertCondition::Immediate { query: r#"regex("x")"#.to_string() },
-            AlertSink::Ntfy { topic: "x".to_string(), server: None },
         );
         assert!(matches!(result, Err(AlertError::NotFound)));
 
@@ -463,7 +445,6 @@ mod tests {
                 threshold: 3.0,
                 window_ms: 10_000,
             },
-            sink: AlertSink::Ntfy { topic: "alerts".to_string(), server: None },
         };
         let mut states = HashMap::new();
         for (seq, ms) in [(0u64, 0i64), (1, 1000)] {
@@ -489,7 +470,6 @@ mod tests {
                 threshold: 2.0,
                 window_ms: 1_000,
             },
-            sink: AlertSink::Ntfy { topic: "alerts".to_string(), server: None },
         };
         let mut states = HashMap::new();
         assert!(evaluate_alerts(&[rule.clone()], &mut states, 0, Timestamp::from_millis(0), "error").is_empty());
@@ -507,7 +487,6 @@ mod tests {
                 field_regex: r"agent=(?P<agent>\S+)".to_string(),
                 capture_group: "agent".to_string(),
             },
-            sink: AlertSink::Ntfy { topic: "alerts".to_string(), server: None },
         };
         let mut states = HashMap::new();
         let fired = evaluate_alerts(&[rule.clone()], &mut states, 0, Timestamp::from_millis(0), "agent=curl");
@@ -531,7 +510,6 @@ mod tests {
                 ratio: 0.5,
                 window_ms: 10_000,
             },
-            sink: AlertSink::Ntfy { topic: "alerts".to_string(), server: None },
         };
         let mut states = HashMap::new();
         // Only an "error" so far; no "request" yet, so denominator is 0 -> skip.