feat: add course search UI with ts-rs type bindings

Integrate ts-rs for Rust-to-TypeScript type generation, build course
search page with filters, pagination, and expandable detail rows,
and refactor theme toggle into a reactive store with view transition
animation.

src/data/models.rs

@@ -3,9 +3,11 @@
 use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
+use ts_rs::TS;
 
 /// Represents a meeting time stored as JSONB in the courses table.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize, TS)]
+#[ts(export)]
 pub struct DbMeetingTime {
     pub begin_time: Option<String>,
     pub end_time: Option<String>,

src/data/reference.rs

@@ -2,6 +2,7 @@
 
 use crate::data::models::ReferenceData;
 use crate::error::Result;
+use html_escape::decode_html_entities;
 use sqlx::PgPool;
 
 /// Batch upsert reference data entries.
@@ -12,7 +13,10 @@ pub async fn batch_upsert(entries: &[ReferenceData], db_pool: &PgPool) -> Result
 
     let categories: Vec<&str> = entries.iter().map(|e| e.category.as_str()).collect();
     let codes: Vec<&str> = entries.iter().map(|e| e.code.as_str()).collect();
-    let descriptions: Vec<&str> = entries.iter().map(|e| e.description.as_str()).collect();
+    let descriptions: Vec<String> = entries
+        .iter()
+        .map(|e| decode_html_entities(&e.description).into_owned())
+        .collect();
 
     sqlx::query(
         r#"