feat: changelog panel with runtime release fetching

Adds a Changelog panel accessible from the nav menu. Fetches all
releases from the Gitea API on open and renders each entry with
version badge, date, pre-release tag, and markdown release notes.
Highlights the currently installed version with a pink "current" badge.

src-tauri/src/commands.rs

@@ -606,6 +606,62 @@ pub async fn check_for_updates() -> Result<UpdateInfo, String> {
     })
 }
 
+#[derive(Debug, serde::Deserialize)]
+struct GiteaChangelogRelease {
+    tag_name: String,
+    html_url: String,
+    body: Option<String>,
+    prerelease: bool,
+    created_at: String,
+}
+
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct ChangelogEntry {
+    pub version: String,
+    pub url: String,
+    pub notes: Option<String>,
+    pub prerelease: bool,
+    pub created_at: String,
+}
+
+#[tauri::command]
+pub async fn fetch_changelog() -> Result<Vec<ChangelogEntry>, String> {
+    const RELEASES_API: &str =
+        "https://git.nhcarrigan.com/api/v1/repos/nhcarrigan/hikari-desktop/releases";
+
+    let client = reqwest::Client::new();
+    let response = client
+        .get(RELEASES_API)
+        .header("Accept", "application/json")
+        .query(&[("limit", "50")])
+        .send()
+        .await
+        .map_err(|e| format!("Failed to fetch releases: {}", e))?;
+
+    if !response.status().is_success() {
+        return Err(format!("API returned status: {}", response.status()));
+    }
+
+    let text = response
+        .text()
+        .await
+        .map_err(|e| format!("Failed to read response: {}", e))?;
+
+    let releases: Vec<GiteaChangelogRelease> =
+        serde_json::from_str(&text).map_err(|e| format!("Failed to parse releases: {}", e))?;
+
+    Ok(releases
+        .into_iter()
+        .map(|r| ChangelogEntry {
+            version: r.tag_name,
+            url: r.html_url,
+            notes: r.body,
+            prerelease: r.prerelease,
+            created_at: r.created_at,
+        })
+        .collect())
+}
+
 #[derive(Debug, Clone, serde::Serialize)]
 pub struct SavedFileInfo {
     pub path: String,

src-tauri/src/lib.rs

@@ -133,6 +133,7 @@ pub fn run() {
             validate_directory,
             list_skills,
             check_for_updates,
+            fetch_changelog,
             save_temp_file,
             register_temp_file,
             get_temp_files,