chore: initialize repository baseline

Import the existing Electron + React + TypeScript app as the version-control
baseline before the scanner rework (C# input/capture sidecar, resolution-anchored
layout profiles, OCR preprocessing, eval harness, rescan-merge, GOOD interop).

Housekeeping in this commit:
- Remove orphaned temp_inputhelper_block.ts (duplicate of the input-helper script).
- Ignore .claude/scheduled_tasks.lock local session state.
- Add .gitattributes to normalize line endings (LF in repo).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

electron/repositories/snapshotRepository.ts

@@ -0,0 +1,27 @@
+import fs from "node:fs/promises";
+import path from "node:path";
+import type { SnapshotRepositoryPort } from "./contracts.js";
+import type { SaveResultWithPath } from "../../src/types/global.js";
+import type { AppSnapshot } from "../../src/types/domain.js";
+
+export class JsonSnapshotRepository implements SnapshotRepositoryPort {
+  private readonly filePath: string;
+
+  constructor(userDataPath: string, fileName = "snapshot.json") {
+    this.filePath = path.join(userDataPath, fileName);
+  }
+
+  async load() {
+    try {
+      return JSON.parse(await fs.readFile(this.filePath, "utf8")) as AppSnapshot;
+    } catch {
+      return null;
+    }
+  }
+
+  async save(snapshot: AppSnapshot): Promise<SaveResultWithPath> {
+    await fs.mkdir(path.dirname(this.filePath), { recursive: true });
+    await fs.writeFile(this.filePath, JSON.stringify(snapshot, null, 2), "utf8");
+    return { ok: true, path: this.filePath };
+  }
+}