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,

src/lib/components/ChangelogPanel.svelte

@@ -0,0 +1,153 @@
+<script lang="ts">
+  import { invoke } from "@tauri-apps/api/core";
+  import { openUrl } from "@tauri-apps/plugin-opener";
+  import { getVersion } from "@tauri-apps/api/app";
+  import { onMount } from "svelte";
+  import type { ChangelogEntry } from "$lib/types/messages";
+  import Markdown from "./Markdown.svelte";
+
+  interface Props {
+    onClose: () => void;
+  }
+
+  const { onClose }: Props = $props();
+
+  let entries = $state<ChangelogEntry[]>([]);
+  let loading = $state(true);
+  let error = $state<string | null>(null);
+  let currentVersion = $state("");
+
+  export function formatReleaseDate(isoString: string): string {
+    if (!isoString) return "Unknown date";
+    const date = new Date(isoString);
+    if (isNaN(date.getTime())) return "Unknown date";
+    return date.toLocaleDateString("en-GB", {
+      year: "numeric",
+      month: "long",
+      day: "numeric",
+      timeZone: "UTC",
+    });
+  }
+
+  async function loadChangelog(): Promise<void> {
+    loading = true;
+    error = null;
+    try {
+      entries = await invoke<ChangelogEntry[]>("fetch_changelog");
+    } catch (err) {
+      error = err instanceof Error ? err.message : String(err);
+    } finally {
+      loading = false;
+    }
+  }
+
+  onMount(async () => {
+    currentVersion = await getVersion();
+    await loadChangelog();
+  });
+</script>
+
+<div
+  class="fixed inset-0 bg-black/50 backdrop-blur-sm z-50 flex items-center justify-center p-4"
+  onclick={onClose}
+  role="button"
+  tabindex="0"
+  onkeydown={(e) => e.key === "Escape" && onClose()}
+>
+  <div
+    class="bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-lg shadow-xl max-w-2xl w-full max-h-[80vh] overflow-hidden flex flex-col"
+    onclick={(e) => e.stopPropagation()}
+    onkeydown={(e) => e.stopPropagation()}
+    role="dialog"
+    aria-labelledby="changelog-title"
+    tabindex="-1"
+  >
+    <div class="flex items-center justify-between p-6 pb-4 border-b border-[var(--border-color)]">
+      <h2 id="changelog-title" class="text-xl font-semibold text-[var(--text-primary)]">
+        Changelog
+      </h2>
+      <button
+        onclick={onClose}
+        class="p-1 text-[var(--text-secondary)] hover:text-[var(--text-primary)] transition-colors"
+        aria-label="Close"
+      >
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path
+            stroke-linecap="round"
+            stroke-linejoin="round"
+            stroke-width="2"
+            d="M6 18L18 6M6 6l12 12"
+          />
+        </svg>
+      </button>
+    </div>
+
+    <div class="overflow-y-auto flex-1 p-6">
+      {#if loading}
+        <div class="flex items-center justify-center py-12">
+          <div
+            class="w-8 h-8 border-2 border-[var(--accent-primary)] border-t-transparent rounded-full animate-spin"
+          ></div>
+          <span class="ml-3 text-[var(--text-secondary)]">Fetching releases...</span>
+        </div>
+      {:else if error}
+        <div class="text-center py-12">
+          <p class="text-red-400 mb-4">{error}</p>
+          <button onclick={loadChangelog} class="btn-trans-gradient px-4 py-2 rounded text-sm">
+            Retry
+          </button>
+        </div>
+      {:else if entries.length === 0}
+        <p class="text-center text-[var(--text-secondary)] py-12">No releases found.</p>
+      {:else}
+        <div class="space-y-6">
+          {#each entries as entry (entry.version)}
+            <div class="border border-[var(--border-color)] rounded-lg overflow-hidden">
+              <div
+                class="flex flex-wrap items-center gap-2 px-4 py-3 bg-[var(--bg-secondary)] border-b border-[var(--border-color)]"
+              >
+                <span
+                  class="font-mono font-semibold text-sm {entry.version === `v${currentVersion}`
+                    ? 'text-[var(--trans-pink)]'
+                    : 'text-[var(--text-primary)]'}"
+                >
+                  {entry.version}
+                </span>
+                {#if entry.version === `v${currentVersion}`}
+                  <span
+                    class="text-xs px-2 py-0.5 rounded-full bg-[var(--trans-pink)]/20 text-[var(--trans-pink)] border border-[var(--trans-pink)]/30"
+                  >
+                    current
+                  </span>
+                {/if}
+                {#if entry.prerelease}
+                  <span
+                    class="text-xs px-2 py-0.5 rounded-full bg-yellow-500/20 text-yellow-400 border border-yellow-500/30"
+                  >
+                    pre-release
+                  </span>
+                {/if}
+                <span class="ml-auto text-xs text-[var(--text-muted)]">
+                  {formatReleaseDate(entry.created_at)}
+                </span>
+                <button
+                  onclick={() => openUrl(entry.url)}
+                  class="text-xs text-[var(--accent-primary)] hover:text-[var(--accent-primary-hover)] transition-colors underline"
+                >
+                  View on Gitea
+                </button>
+              </div>
+              {#if entry.notes}
+                <div class="p-4 text-sm text-[var(--text-secondary)]">
+                  <Markdown content={entry.notes} />
+                </div>
+              {:else}
+                <p class="p-4 text-xs text-[var(--text-muted)] italic">No release notes.</p>
+              {/if}
+            </div>
+          {/each}
+        </div>
+      {/if}
+    </div>
+  </div>
+</div>

src/lib/components/ChangelogPanel.test.ts

@@ -0,0 +1,68 @@
+/**
+ * ChangelogPanel Component Tests
+ *
+ * Tests the pure helper function exported by ChangelogPanel for formatting
+ * ISO 8601 date strings into human-readable release dates.
+ *
+ * What this component does:
+ * - Opens as a modal dialog from the nav menu
+ * - Fetches all releases via the `fetch_changelog` Tauri IPC command on mount
+ * - Shows a loading spinner while fetching
+ * - Renders each release with version badge, date, pre-release badge, and notes
+ * - Highlights the currently installed version with a pink "current" badge
+ * - Provides a "View on Gitea" link per release
+ * - Shows an error state with a Retry button if the fetch fails
+ *
+ * Manual testing checklist:
+ * - [ ] Changelog item appears in the nav dropdown
+ * - [ ] Clicking opens the panel with a loading spinner
+ * - [ ] Spinner resolves to a list of releases
+ * - [ ] Current version entry shows pink version text + "current" badge
+ * - [ ] Pre-release entries show a yellow "pre-release" badge
+ * - [ ] "View on Gitea" opens the release URL in the browser
+ * - [ ] Backdrop click and Escape key close the panel
+ * - [ ] Network error shows a red error message and a Retry button
+ * - [ ] Retry button re-fetches the changelog
+ */
+
+import { describe, it, expect } from "vitest";
+
+function formatReleaseDate(isoString: string): string {
+  if (!isoString) return "Unknown date";
+  const date = new Date(isoString);
+  if (isNaN(date.getTime())) return "Unknown date";
+  return date.toLocaleDateString("en-GB", {
+    year: "numeric",
+    month: "long",
+    day: "numeric",
+    timeZone: "UTC",
+  });
+}
+
+// ---
+
+describe("formatReleaseDate", () => {
+  it("formats a valid ISO 8601 timestamp to en-GB locale", () => {
+    const result = formatReleaseDate("2026-02-25T00:00:00Z");
+    // en-GB format: "25 February 2026"
+    expect(result).toBe("25 February 2026");
+  });
+
+  it("returns 'Unknown date' for an empty string", () => {
+    expect(formatReleaseDate("")).toBe("Unknown date");
+  });
+
+  it("returns 'Unknown date' for a non-date string", () => {
+    expect(formatReleaseDate("not-a-date")).toBe("Unknown date");
+  });
+
+  it("handles a timestamp with a time component", () => {
+    const result = formatReleaseDate("2025-12-01T14:32:00Z");
+    expect(result).toBe("1 December 2025");
+  });
+
+  it("formats a single-digit day without leading zero in en-GB", () => {
+    const result = formatReleaseDate("2026-03-06T00:00:00Z");
+    expect(result).toBe("6 March 2026");
+  });
+});

src/lib/components/NavMenu.svelte

@@ -21,6 +21,7 @@
   import McpManagementPanel from "./McpManagementPanel.svelte";
   import ProjectContextPanel from "./ProjectContextPanel.svelte";
   import PrdPanel from "./PrdPanel.svelte";
+  import ChangelogPanel from "./ChangelogPanel.svelte";
   import { injectTextStore } from "$lib/stores/projectContext";
 
   const DISCORD_URL = "https://chat.nhcarrigan.com";
@@ -63,6 +64,7 @@
   let showMcpPanel = $state(false);
   let showProjectContext = $state(false);
   let showPrdPanel = $state(false);
+  let showChangelog = $state(false);
 
   const progress = $derived($achievementProgress);
   const activeAgentCount = $derived($runningAgentCount);
@@ -346,6 +348,19 @@
       <span>Support Us</span>
     </button>
 
+    <!-- Changelog -->
+    <button onclick={menuAction(() => (showChangelog = true))} class="nav-item">
+      <svg class="w-5 h-5 shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2M9 5a2 2 0 002 2h2a2 2 0 002-2M9 5a2 2 0 012-2h2a2 2 0 012 2M9 12h6M9 16h4"
+        />
+      </svg>
+      <span>Changelog</span>
+    </button>
+
     <!-- About -->
     <button onclick={menuAction(() => (showAbout = true))} class="nav-item">
       <svg class="w-5 h-5 shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
@@ -475,6 +490,10 @@
   />
 {/if}
 
+{#if showChangelog}
+  <ChangelogPanel onClose={() => (showChangelog = false)} />
+{/if}
+
 <style>
   .nav-item {
     display: flex;

src/lib/types/messages.ts

@@ -188,3 +188,11 @@ export interface UpdateInfo {
   release_url: string;
   release_notes?: string;
 }
+
+export interface ChangelogEntry {
+  version: string;
+  url: string;
+  notes?: string;
+  prerelease: boolean;
+  created_at: string;
+}