try to use local ai to generate commit message

src/App.svelte

@@ -25,6 +25,8 @@
   import {
     checkoutBranch,
     commit,
+    commitAiGenerate,
+    commitAiStatus,
     compareCommits,
     cancelCodeSearch,
     cancelFileHistory,
@@ -62,6 +64,7 @@
   } from "./lib/git";
 
   import type {
+    CommitAiPhase,
     ConflictFile,
     ExplorerNode,
     ExplorerNodeKind,
@@ -122,7 +125,11 @@
   let fileHistoryLoading = false;
   let fileHistoryRequestId = 0;
   let activeFileHistoryRequestId = "";
+  let lastFileHistoryHeadHash = "";
   let commitMessage = "";
+  let commitAiPhase: CommitAiPhase = "idle";
+  let commitAiGenerating = false;
+  let commitAiPollTimer: ReturnType<typeof setInterval> | undefined;
   let errorMessage = "";
   let operation = "";
   let compareFrom = "";
@@ -206,10 +213,12 @@
     loadRepoLists();
     autoRefreshTimer = setInterval(() => { void autoRefreshTick(); }, AUTO_REFRESH_INTERVAL);
     void checkForUpdates();
+    startCommitAiPolling();
   });
 
   onDestroy(() => {
     if (autoRefreshTimer) clearInterval(autoRefreshTimer);
+    if (commitAiPollTimer) clearInterval(commitAiPollTimer);
     if (activeFileHistoryRequestId) void cancelFileHistory(activeFileHistoryRequestId);
   });
 
@@ -229,15 +238,54 @@
       applyStatus(nextStatus);
       // Something changed — reload branches, commits and files in one bundled call.
       const bundle = await openRepositoryBundle(activeRepoPath, 100);
+      const previousHeadHash = lastFileHistoryHeadHash;
       await refreshBranchList(activeRepoPath, bundle.branches);
       await refreshCommitHistory(activeRepoPath, bundle.commits);
       await refreshExplorerFiles(activeRepoPath, bundle.files);
-      await refreshFileHistory(activeRepoPath);
+      // File history reflects `git log`, which only changes when HEAD actually moves
+      // (new commit, checkout, merge, ...) — skip the reload otherwise so a plain
+      // working-tree/status change (staging, edits) doesn't keep re-fetching and
+      // flickering the currently viewed file's history.
+      if (lastFileHistoryHeadHash !== previousHeadHash) {
+        await refreshFileHistory(activeRepoPath);
+      }
     } catch { /* ignore transient errors */ } finally {
       autoRefreshInFlight = false;
     }
   }
 
+  // ── Commit AI ──────────────────────────────────────────────────────────────
+
+  async function pollCommitAiStatus() {
+    try {
+      const result = await commitAiStatus();
+      commitAiPhase = result.phase;
+    } catch { /* ignore transient errors */ }
+    if (commitAiPhase === "ready" || commitAiPhase === "error") {
+      if (commitAiPollTimer) { clearInterval(commitAiPollTimer); commitAiPollTimer = undefined; }
+    }
+  }
+
+  function startCommitAiPolling() {
+    // The model downloads (first run only) and loads in the background on app start;
+    // poll until it's ready (or failed) so the "AI" button can enable itself.
+    void pollCommitAiStatus();
+    commitAiPollTimer = setInterval(() => { void pollCommitAiStatus(); }, 2000);
+  }
+
+  async function generateCommitMessageWithAi() {
+    if (!activeRepoPath || commitAiPhase !== "ready" || commitAiGenerating) return;
+    commitAiGenerating = true;
+    errorMessage = "";
+    try {
+      commitMessage = await commitAiGenerate(activeRepoPath, commitMessage.trim() || undefined);
+    } catch (error) {
+      errorMessage = errorToMessage(error);
+    } finally {
+      commitAiGenerating = false;
+    }
+  }
+
   function toggleAutoRefresh() {
     autoRefreshEnabled = !autoRefreshEnabled;
     if (autoRefreshEnabled) void autoRefreshTick();
@@ -430,6 +478,7 @@
     }
     branches = [];
     commits = [];
+    lastFileHistoryHeadHash = "";
     repoFiles = [];
     selectedExplorerPath = "";
     selectedExplorerKind = "file";
@@ -520,6 +569,7 @@
 
   async function refreshCommitHistory(path = activeRepoPath, prefetched?: GitCommit[]) {
     commits = prefetched ?? (await listCommits(path, 100));
+    lastFileHistoryHeadHash = commits[0]?.hash ?? "";
     const hashes = new Set(commits.map((c) => c.hash));
     if (compareFrom && !hashes.has(compareFrom)) compareFrom = "";
     if (compareTo && !hashes.has(compareTo)) compareTo = "";
@@ -1692,8 +1742,11 @@
             {isBusy}
             {operation}
             {stagedCount}
+            {commitAiPhase}
+            {commitAiGenerating}
             onCommit={commitChanges}
             onCommitMessageChange={(msg) => { commitMessage = msg; }}
+            onGenerateCommitMessage={generateCommitMessageWithAi}
           />
         </div>
       </section>