feat(git): add rebase workflow with UI state handling

This introduces Git rebase commands (start, continue, abort) and
exposes whether a rebase is currently in progress via the status
payload. The UI now blocks committing during an active rebase and
shows a dedicated rebase notice with continue/abort actions.

- Add tauri commands for rebase operations and status detection
- Update frontend to render rebase state and controls
- Adjust conflict/resolution messaging and related UI styling

src/App.svelte

@@ -54,6 +54,9 @@
     pull,
     push,
     renameBranch,
+    rebaseAbort,
+    rebaseBranch,
+    rebaseContinue,
     getRemoteUrl,
     credLoad,
     credSave,
@@ -236,9 +239,12 @@
   $: unstagedCount = status?.files.filter((f) => f.unstaged !== null).length ?? 0;
   $: conflictedFiles = changedFiles.filter((f) => f.staged === "conflicted" || f.unstaged === "conflicted");
   $: hasConflicts = conflictedFiles.length > 0;
-  $: canCommit = hasRepository && stagedCount > 0 && commitMessage.trim().length > 0 && !hasConflicts && !isBusy;
-  $: commitBlockReason = hasConflicts
-    ? `${conflictedFiles.length} ${conflictedFiles.length === 1 ? "merge conflict must" : "merge conflicts must"} be resolved before committing.`
+  $: rebaseInProgress = status?.rebase_in_progress ?? false;
+  $: canCommit = hasRepository && stagedCount > 0 && commitMessage.trim().length > 0 && !hasConflicts && !rebaseInProgress && !isBusy;
+  $: commitBlockReason = rebaseInProgress
+    ? "A rebase is in progress. Resolve conflicts and use Rebase continue or abort the rebase."
+    : hasConflicts
+    ? `${conflictedFiles.length} ${conflictedFiles.length === 1 ? "conflict must" : "conflicts must"} be resolved before committing.`
     : "";
   $: canCompare = hasRepository && compareFrom.length > 0 && compareTo.length > 0 && compareFrom !== compareTo && !isBusy;
   $: localBranches = branches.filter((b) => !b.remote);
@@ -1120,6 +1126,46 @@
     });
   }
 
+  async function rebaseOnto(branch: GitBranchInfo) {
+    if (!activeRepoPath || branch.current || rebaseInProgress) return;
+    await runOperation(`Rebasing onto ${branch.name}`, async () => {
+      applyStatus(await rebaseBranch(activeRepoPath, branch.name));
+      await refreshBranchList(activeRepoPath);
+      await refreshCommitHistory(activeRepoPath);
+      await refreshExplorerFiles(activeRepoPath);
+      await refreshFileHistory(activeRepoPath);
+    });
+  }
+
+  async function continueRebase() {
+    if (!activeRepoPath || !rebaseInProgress || hasConflicts) return;
+    await runOperation("Continuing rebase", async () => {
+      applyStatus(await rebaseContinue(activeRepoPath));
+      await refreshBranchList(activeRepoPath);
+      await refreshCommitHistory(activeRepoPath);
+      await refreshExplorerFiles(activeRepoPath);
+      await refreshFileHistory(activeRepoPath);
+    });
+  }
+
+  async function abortRebase() {
+    if (!activeRepoPath || !rebaseInProgress) return;
+    const confirmed = window.confirm("Abort the current rebase and return to the previous state?");
+    if (!confirmed) return;
+
+    await runOperation("Aborting rebase", async () => {
+      applyStatus(await rebaseAbort(activeRepoPath));
+      preparedResolutions = {};
+      resolveDialogOpen = false;
+      conflict = null;
+      conflictTarget = "";
+      await refreshBranchList(activeRepoPath);
+      await refreshCommitHistory(activeRepoPath);
+      await refreshExplorerFiles(activeRepoPath);
+      await refreshFileHistory(activeRepoPath);
+    });
+  }
+
   // Resolve the keychain key (host/org) for the active repo's remote.
   async function currentCredKey(): Promise<string | null> {
     if (!activeRepoPath) return null;
@@ -1519,7 +1565,11 @@
     const message = commitMessage.trim();
     if (!message || !activeRepoPath) return;
     if (hasConflicts) {
-      errorMessage = "Resolve all merge conflicts before committing.";
+      errorMessage = "Resolve all conflicts before committing.";
+      return;
+    }
+    if (rebaseInProgress) {
+      errorMessage = "A rebase is in progress. Use Rebase continue or abort the rebase.";
       return;
     }
     await runOperation("Committing", async () => {
@@ -1939,14 +1989,33 @@
       </section>
     {/if}
 
-    {#if workspaceActive && hasConflicts}
+    {#if workspaceActive && hasConflicts && !rebaseInProgress}
       <section class="notice conflict" role="alert">
         <GitMerge size={17} aria-hidden="true" />
-        <span>{conflictedFiles.length} {conflictedFiles.length === 1 ? "file has" : "files have"} merge conflicts.</span>
+        <span>{conflictedFiles.length} {conflictedFiles.length === 1 ? "file has" : "files have"} conflicts.</span>
         <button type="button" onclick={openResolveDialog} disabled={isBusy}>Resolve conflicts</button>
       </section>
     {/if}
 
+    {#if workspaceActive && rebaseInProgress}
+      <section class="notice rebase" role="status">
+        <GitBranch size={17} aria-hidden="true" />
+        <span>
+          Rebase in progress.
+          {#if hasConflicts}
+            Resolve conflicts, then continue.
+          {:else}
+            Continue when the index is ready, or abort to return to the previous state.
+          {/if}
+        </span>
+        {#if hasConflicts}
+          <button type="button" onclick={openResolveDialog} disabled={isBusy}>Resolve conflicts</button>
+        {/if}
+        <button type="button" onclick={continueRebase} disabled={isBusy || hasConflicts}>Continue</button>
+        <button type="button" onclick={abortRebase} disabled={isBusy}>Abort</button>
+      </section>
+    {/if}
+
     {#if activeView === "management"}
       <section class="repo-management" aria-label="Repository Management">
         <div class="repo-management-head">
@@ -2073,6 +2142,7 @@
           {isBusy}
           onCheckout={checkout}
           onMerge={merge}
+          onRebase={rebaseOnto}
           onCreateBranch={createNewBranch}
           onRenameBranch={renameLocalBranch}
           onDeleteBranch={deleteLocalBranch}