add day time unit for ratelimits

PR #851 added ratelimit examples using unit: day but the Rust
TimeUnit enum only had second/minute/hour. Adds Day variant and
maps it to per-hour quota (tokens/24).

crates/common/src/configuration.rs

@@ -290,6 +290,8 @@ pub enum TimeUnit {
     Minute,
     #[serde(rename = "hour")]
     Hour,
+    #[serde(rename = "day")]
+    Day,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, Hash)]

crates/common/src/ratelimit.rs

@@ -150,6 +150,10 @@ fn get_quota(limit: Limit) -> Quota {
         TimeUnit::Second => Quota::per_second(tokens),
         TimeUnit::Minute => Quota::per_minute(tokens),
         TimeUnit::Hour => Quota::per_hour(tokens),
+        TimeUnit::Day => {
+            let per_hour = limit.tokens.saturating_div(24).max(1);
+            Quota::per_hour(NonZero::new(per_hour).expect("per_hour must be positive"))
+        }
     }
 }