feat: MVP-2 completion - search, quick add, backlinks, guided forms

## Search & Retrieval
- Improved search ranking with scoring (title match, favorites, recency)
- Highlight matches with excerpt extraction
- Fuzzy search with string-similarity
- Unified noteQuery function

## Quick Capture
- Quick Add API (POST /api/notes/quick) with type prefixes
- Quick add parser with tag extraction
- Global Quick Add UI (Ctrl+N shortcut)
- Tag autocomplete in forms

## Note Relations
- Automatic backlinks with sync on create/update/delete
- Backlinks API (GET /api/notes/[id]/backlinks)
- Related notes with scoring and reasons

## Guided Forms
- Type-specific form fields (command, snippet, decision, recipe, procedure, inventory)
- Serialization to/from markdown
- Tag suggestions based on content (GET /api/tags/suggest)

## UX by Type
- Command: Copy button for code blocks
- Snippet: Syntax highlighting with react-syntax-highlighter
- Procedure: Interactive checkboxes

## Quality
- Standardized error handling across all APIs
- Integration tests (28 tests passing)
- Unit tests for search, tags, quick-add

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

jest.config.js

@@ -0,0 +1,27 @@
+/** @type {import('jest').Config} */
+const config = {
+  testEnvironment: 'node',
+  moduleNameMapper: {
+    '^@/(.*)$': '<rootDir>/src/$1',
+  },
+  transform: {
+    '^.+\\.(ts|tsx)$': ['ts-jest', {
+      tsconfig: {
+        jsx: 'react-jsx',
+        esModuleInterop: true,
+      },
+    }],
+  },
+  testMatch: [
+    '**/__tests__/**/*.test.ts',
+    '**/__tests__/**/*.test.tsx',
+  ],
+  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
+  collectCoverageFrom: [
+    'src/**/*.{ts,tsx}',
+    '!src/**/*.d.ts',
+    '!src/**/*.test.{ts,tsx}',
+  ],
+}
+
+module.exports = config