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/lib/components/CompareDialog.svelte

@@ -15,6 +15,8 @@
     selectedDiffPath: string;
     isBusy: boolean;
     restoreLabel?: string;
+    /** When opened from a search hit, the term to highlight on matching lines. */
+    highlightQuery?: string;
     onClose: () => void;
     onRestore?: () => void;
     onSelectFile: (file: GitDiffFile) => void;
@@ -25,11 +27,25 @@
     selectedDiffPath = "",
     isBusy = false,
     restoreLabel = "",
+    highlightQuery = "",
     onClose = () => {},
     onRestore = undefined,
     onSelectFile = () => {},
   }: Props = $props();
 
+  // Needle = first non-empty line of the search query, lowercased for matching.
+  let highlightNeedle = $derived(
+    highlightQuery
+      .split("\n")
+      .map((line) => line.trim())
+      .find((line) => line.length > 0)
+      ?.toLowerCase() ?? ""
+  );
+
+  function isMatch(text?: string): boolean {
+    return highlightNeedle.length > 0 && !!text && text.toLowerCase().includes(highlightNeedle);
+  }
+
   let beforePane = $state<HTMLDivElement | null>(null);
   let afterPane = $state<HTMLDivElement | null>(null);
   let isSyncingSplitScroll = false;
@@ -259,8 +275,8 @@
                     {#if row.type === "span"}
                       <div class="split-span split-{row.kind}">{row.text}</div>
                     {:else}
-                      <div class="split-num" class:del={row.leftKind === "del"} class:empty={row.leftKind === "empty"}>{row.leftNum ?? ""}</div>
-                      <div class="split-cell" class:del={row.leftKind === "del"} class:empty={row.leftKind === "empty"}>{row.leftText ?? " "}</div>
+                      <div class="split-num" class:del={row.leftKind === "del"} class:empty={row.leftKind === "empty"} class:match={isMatch(row.leftText)}>{row.leftNum ?? ""}</div>
+                      <div class="split-cell" class:del={row.leftKind === "del"} class:empty={row.leftKind === "empty"} class:match={isMatch(row.leftText)}>{row.leftText ?? " "}</div>
                     {/if}
                   {/each}
                 </div>
@@ -276,8 +292,8 @@
                     {#if row.type === "span"}
                       <div class="split-span split-{row.kind}">{row.text}</div>
                     {:else}
-                      <div class="split-num" class:add={row.rightKind === "add"} class:empty={row.rightKind === "empty"}>{row.rightNum ?? ""}</div>
-                      <div class="split-cell" class:add={row.rightKind === "add"} class:empty={row.rightKind === "empty"}>{row.rightText ?? " "}</div>
+                      <div class="split-num" class:add={row.rightKind === "add"} class:empty={row.rightKind === "empty"} class:match={isMatch(row.rightText)}>{row.rightNum ?? ""}</div>
+                      <div class="split-cell" class:add={row.rightKind === "add"} class:empty={row.rightKind === "empty"} class:match={isMatch(row.rightText)}>{row.rightText ?? " "}</div>
                     {/if}
                   {/each}
                 </div>

src/lib/components/GlobalSearchDialog.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { CalendarDays, FileCode, LoaderCircle, Search, User, X } from "@lucide/svelte";
+  import { CalendarDays, FileCode, GitCompare, LoaderCircle, Search, User, X } from "@lucide/svelte";
   import type { GitSearchHit } from "../types";
 
   interface Props {
@@ -11,6 +11,7 @@
     onClose: () => void;
     onSearch: (query: string, caseSensitive: boolean, limit: number) => void | Promise<void>;
     onCancel: () => void | Promise<void>;
+    onDiff: (hit: GitSearchHit) => void | Promise<void>;
   }
 
   let {
@@ -22,6 +23,7 @@
     onClose = () => {},
     onSearch = () => {},
     onCancel = () => {},
+    onDiff = () => {},
   }: Props = $props();
 
   let query = $state("");
@@ -148,6 +150,16 @@
                   {#if hit.matches_added > 1}
                     <span class="pill pill-active">+{hit.matches_added} matches</span>
                   {/if}
+                  <button
+                    class="btn-secondary search-hit-diff"
+                    type="button"
+                    disabled={isBusy}
+                    title={`Compare this version of ${hit.file} with the current version`}
+                    onclick={() => onDiff(hit)}
+                  >
+                    <GitCompare size={14} aria-hidden="true" />
+                    DIFF
+                  </button>
                 </header>
 
                 <div class="search-hit-meta">