fix: remaining unwrap panics and new bugs discovered during audit

- email worker: replace Mailbox::parse().unwrap() with match to
  handle invalid recipient addresses gracefully
- metrics middleware: RwLock poison recovery on read/write locks
  to prevent panic on thread panic
- access key: SystemTime::now() unwrap_or_default instead of unwrap
  for clock-before-epoch edge case
- chpc: NaiveDateTime and_hms_opt unwrap_or MIN/MAX fallbacks
- push notification: second code path fixed for let-chain unwrap
- ai_streaming: constant UUID parse use expect() instead of unwrap

libs/email/lib.rs

@@ -64,16 +64,20 @@ impl AppEmail {
 
         tokio::spawn(async move {
             while let Some(msg) = rx.recv().await {
-                if !EMAIL_REGEX.is_match(&msg.clone().to) {
-                    counter!("email_validation_skipped_total").increment(1);
-                    continue;
-                }
+                let recipient: Mailbox = match msg.to.parse() {
+                    Ok(addr) => addr,
+                    Err(_) => {
+                        counter!("email_validation_skipped_total").increment(1);
+                        tracing::warn!(to = %msg.to, "Invalid recipient address");
+                        continue;
+                    }
+                };
 
                 let email = match lettre::Message::builder()
                     .from(from.clone())
-                    .to(msg.clone().to.parse().unwrap())
-                    .subject(msg.clone().subject)
-                    .body(msg.clone().body)
+                    .to(recipient)
+                    .subject(msg.subject)
+                    .body(msg.body)
                 {
                     Ok(e) => e,
                     Err(_) => {

libs/observability/src/metrics_middleware.rs

@@ -37,7 +37,7 @@ impl HttpMetrics {
     /// Increment the counter for a specific HTTP endpoint (method + path).
     pub fn incr_endpoint(&self, method: &str, path: &str) {
         let key = format!("{} {}", method, path);
-        let mut map = self.endpoint_counts.write().unwrap();
+        let mut map = self.endpoint_counts.write().unwrap_or_else(|e| e.into_inner());
         let counter = map.entry(key).or_insert_with(|| AtomicU64::new(0));
         counter.fetch_add(1, Ordering::Relaxed);
     }
@@ -52,7 +52,7 @@ impl HttpMetrics {
         m.insert("http_requests_5xx".into(), serde_json::json!(self.status_5xx.load(Ordering::Relaxed)));
 
         // Per-endpoint counters
-        let map = self.endpoint_counts.read().unwrap();
+        let map = self.endpoint_counts.read().unwrap_or_else(|e| e.into_inner());
         for (key, counter) in map.iter() {
             // Sanitize key for use as metric name: replace spaces and slashes with underscores
             let sanitized = key.replace([' ', '/'], "_").to_lowercase();

libs/service/user/access_key.rs

@@ -214,7 +214,7 @@ impl AppService {
         use std::time::{SystemTime, UNIX_EPOCH};
         let now = SystemTime::now()
             .duration_since(UNIX_EPOCH)
-            .unwrap()
+            .unwrap_or_default()
             .as_nanos();
         let chars: Vec<char> = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
             .chars()

libs/service/user/chpc.rs

@@ -78,8 +78,8 @@ impl AppService {
             return Ok(response);
         }
 
-        let start_dt = start_date.and_hms_opt(0, 0, 0).unwrap();
-        let end_dt = end_date.and_hms_opt(23, 59, 59).unwrap();
+        let start_dt = start_date.and_hms_opt(0, 0, 0).unwrap_or(chrono::NaiveDateTime::MIN);
+        let end_dt = end_date.and_hms_opt(23, 59, 59).unwrap_or(chrono::NaiveDateTime::MAX);
 
         let commits: Vec<repo_commit::Model> = repo_commit::Entity::find()
             .filter(repo_commit::Column::AuthorEmail.is_in(emails.clone()))