Add unified search query model with regex/whole-word support for find/replace.

M8 find/replace polish: a tested SearchQuery contract (searchQuery.ts) drives
both in-file editor search and project-wide search through @codemirror/search's
RegExpCursor. Editor ops, highlight, domain APIs, host factory, and types all
consume SearchQuery objects. Project search extends matches with to/length,
validates before traversal, and routes replace through the existing dirty-doc
safety gate. FindReplacePanel gains match-case/whole-word/regex toggles,
inline regex validation, selection seeding, and responsive width.
ProjectSearchPanel gains the same toggles, confirmation dialog before
replace-all, and cancellable search on workspace switch/close.

282 test files, 2960 tests pass. npm run check: 0 errors.

Author: Alexey Perov

README.md

@@ -8,7 +8,9 @@ and **OpenCode**-powered workspace sessions. Built with
 
 ## What works today
 
-- **Editor** — syntax highlighting for Markdown and common code languages; optional **minimap**
+- **Editor** — syntax highlighting for Markdown and common code languages; optional **minimap**;
+  multi-cursor, code folding, Markdown outline; find/replace with regex, whole-word,
+  and case matching in-file and across the project
 - **Markdown** preview and edit
 - **Folders as workspaces** — multi-root activity rail
 - **Project panel** — file tree, drag-and-drop move, context menu (new/rename/delete), live refresh, tabs, show/hide hidden files

app/src/lib/components/AppShell.svelte

@@ -227,6 +227,10 @@
     query: string;
     replaceValue: string;
     caseSensitive: boolean;
+    wholeWord: boolean;
+    regex: boolean;
+    /** Inline regex validation error (empty string when the query is valid). */
+    queryError: string;
     results: import("../services/projectSearch").ProjectSearchResult[];
     running: boolean;
     status: string;
@@ -236,6 +240,8 @@
     onQueryChange: (value: string) => void;
     onReplaceValueChange: (value: string) => void;
     onCaseSensitiveChange: (value: boolean) => void;
+    onWholeWordChange: (value: boolean) => void;
+    onRegexChange: (value: boolean) => void;
     onRunSearch: () => void;
     onReplaceAll: () => void;
     onOpenResult: (path: string, line: number) => void;
@@ -596,6 +602,9 @@
         query={projectSearch.query}
         replaceValue={projectSearch.replaceValue}
         caseSensitive={projectSearch.caseSensitive}
+        wholeWord={projectSearch.wholeWord}
+        regex={projectSearch.regex}
+        queryError={projectSearch.queryError}
         results={projectSearch.results}
         running={projectSearch.running}
         status={projectSearch.status}
@@ -604,6 +613,8 @@
         onQueryChange={projectSearch.onQueryChange}
         onReplaceValueChange={projectSearch.onReplaceValueChange}
         onCaseSensitiveChange={projectSearch.onCaseSensitiveChange}
+        onWholeWordChange={projectSearch.onWholeWordChange}
+        onRegexChange={projectSearch.onRegexChange}
         onRunSearch={projectSearch.onRunSearch}
         onReplaceAll={projectSearch.onReplaceAll}
         onOpenResult={projectSearch.onOpenResult}

app/src/lib/components/EditorPaneContent.svelte

@@ -158,12 +158,23 @@
   let findQuery = $state("");
   let replaceValue = $state("");
   let findCaseSensitive = $state(false);
+  let findWholeWord = $state(false);
+  let findRegexp = $state(false);
   let goToLineValue = $state("");
+  /**
+   * Text captured from the editor's main selection at the moment Find opens.
+   * Used to seed the query when the selection is non-empty and single-ranged;
+   * empty when there is nothing useful to seed.
+   */
+  let findReplaceSeedSelection = $state("");
+  let prevFindReplaceOpen = false;
 
   $effect(() => {
     findQuery = toolSnapshot.find.query;
     replaceValue = toolSnapshot.find.replace;
     findCaseSensitive = toolSnapshot.find.caseSensitive;
+    findWholeWord = toolSnapshot.find.wholeWord;
+    findRegexp = toolSnapshot.find.regexp;
     goToLineValue = toolSnapshot.goToLineValue;
   });
 
@@ -176,10 +187,37 @@
   $effect(() => {
     editorTools.setFindCaseSensitive(findCaseSensitive);
   });
+  $effect(() => {
+    editorTools.setFindWholeWord(findWholeWord);
+  });
+  $effect(() => {
+    editorTools.setFindRegexp(findRegexp);
+  });
   $effect(() => {
     editorTools.setGoToLineValue(goToLineValue);
   });
 
+  // Seed the find query from a non-empty single selection when Find opens.
+  $effect(() => {
+    const isOpen = findReplaceOpen;
+    if (isOpen && !prevFindReplaceOpen) {
+      const host = getActiveEditorHost();
+      const selResult = host?.queries.selection.getSelection();
+      if (host && selResult?.ok && !selResult.value.empty) {
+        const docResult = host.queries.document.getDocumentContent();
+        if (docResult.ok) {
+          findReplaceSeedSelection = docResult.value.slice(
+            selResult.value.from,
+            selResult.value.to,
+          );
+        }
+      } else {
+        findReplaceSeedSelection = "";
+      }
+    }
+    prevFindReplaceOpen = isOpen;
+  });
+
   let paneSectionEl = $state<HTMLElement | null>(null);
 
   const layout = $derived(session.editorLayout);
@@ -387,6 +425,9 @@
       bind:findQuery
       bind:replaceValue
       bind:findCaseSensitive
+      bind:findWholeWord
+      bind:findRegexp
+      seedSelection={findReplaceSeedSelection}
       getEditorRunner={getActiveEditorRunner}
       {notify}
       documentId={paneDocument?.id ?? null}