Improve global search: Add diffing from results with query highlighting

Users can now open a diff for a specific search hit directly from the global search results. The original search query will be highlighted within the diff view, making it easier to locate the relevant changes.

Additionally, add `--no-textconv` to git commands used in search and diff operations. This prevents failures when git encounters binary files that textconv drivers might otherwise attempt to process.

src/App.svelte

@@ -96,8 +96,10 @@
   let comparison: GitCommitComparison | null = null;
   let compareDialogOpen = false;
   let selectedDiffPath = "";
+  let diffHighlightQuery = "";
   let pendingRestoreFile: { commit: GitCommit; file: GitCommitFile } | null = null;
   let globalSearchOpen = false;
+  let lastSearchQuery = "";
   let globalSearchResults: GitSearchHit[] = [];
   let globalSearchBusy = false;
   let globalSearchError = "";
@@ -746,6 +748,7 @@
       const result = await compareCommits(activeRepoPath, compareFrom, compareTo);
       comparison = result;
       selectedDiffPath = result.files[0]?.path ?? "";
+      diffHighlightQuery = "";
       pendingRestoreFile = null;
       compareDialogOpen = true;
     });
@@ -757,6 +760,19 @@
       const result = await diffFileAgainstWorkingTree(activeRepoPath, historyCommit.hash, selectedExplorerPath);
       comparison = result;
       selectedDiffPath = result.files[0]?.path ?? selectedExplorerPath;
+      diffHighlightQuery = "";
+      pendingRestoreFile = null;
+      compareDialogOpen = true;
+    });
+  }
+
+  async function diffSearchHit(hit: GitSearchHit) {
+    if (!activeRepoPath) return;
+    await runOperation(`Diffing ${hit.file}`, async () => {
+      const result = await diffFileAgainstWorkingTree(activeRepoPath, hit.commit_hash, hit.file);
+      comparison = result;
+      selectedDiffPath = result.files[0]?.path ?? hit.file;
+      diffHighlightQuery = lastSearchQuery;
       pendingRestoreFile = null;
       compareDialogOpen = true;
     });
@@ -785,6 +801,7 @@
     if (!activeRepoPath || globalSearchBusy) return;
     const searchId = `search-${Date.now()}-${Math.random().toString(36).slice(2)}`;
     globalSearchId = searchId;
+    lastSearchQuery = query;
     globalSearchBusy = true;
     globalSearchError = "";
     globalSearchResults = [];
@@ -1109,19 +1126,6 @@
   />
 {/if}
 
-<!-- Compare diff dialog -->
-{#if compareDialogOpen && comparison}
-  <CompareDialog
-    {comparison}
-    {selectedDiffPath}
-    {isBusy}
-    restoreLabel={pendingRestoreFile ? "Restore file" : ""}
-    onClose={closeCompareDialog}
-    onRestore={restorePreviewedCommitFile}
-    onSelectFile={selectDiffFile}
-  />
-{/if}
-
 {#if globalSearchOpen}
   <GlobalSearchDialog
     {hasRepository}
@@ -1132,6 +1136,21 @@
     onClose={closeGlobalSearchDialog}
     onSearch={runGlobalSearch}
     onCancel={cancelGlobalSearch}
+    onDiff={diffSearchHit}
+  />
+{/if}
+
+<!-- Compare diff dialog (rendered last so it overlays the search dialog when opened from a hit) -->
+{#if compareDialogOpen && comparison}
+  <CompareDialog
+    {comparison}
+    {selectedDiffPath}
+    {isBusy}
+    highlightQuery={diffHighlightQuery}
+    restoreLabel={pendingRestoreFile ? "Restore file" : ""}
+    onClose={closeCompareDialog}
+    onRestore={restorePreviewedCommitFile}
+    onSelectFile={selectDiffFile}
   />
 {/if}