test: comprehensive coverage for NoteTools

Add extensive test suite for note-tools.ts covering all major operations
and error paths. Improves statement coverage from 13.94% to 96.01%.

Tests added:
- readNote: success, errors, frontmatter parsing
- createNote: success, conflict strategies (error/overwrite/rename), parent folder creation
- updateNote: success, errors, waypoint protection
- deleteNote: soft/permanent delete, dry run, version checking
- renameFile: success, errors, version checking, parent folder creation
- readExcalidraw: success, non-Excalidraw files, errors
- updateFrontmatter: success, field removal, version checking
- updateSections: success, invalid ranges, version checking
- Path validation for all methods
- Empty path validation for all methods

Mock enhancements:
- Added modify, delete, trash methods to VaultAdapter mock
- Added parseYaml function to Obsidian mock for frontmatter testing

Coverage improvements for note-tools.ts:
- Statements: 13.94% -> 96.01% (+82.07%)
- Branches: 5.1% -> 88.44% (+83.34%)
- Functions: 27.27% -> 90.9% (+63.63%)
- Lines: 13.94% -> 96.4% (+82.46%)

tests/__mocks__/adapters.ts

@@ -14,6 +14,9 @@ export function createMockVaultAdapter(overrides?: Partial<IVaultAdapter>): IVau
 		process: jest.fn(),
 		createFolder: jest.fn(),
 		create: jest.fn(),
+		modify: jest.fn(),
+		delete: jest.fn(),
+		trash: jest.fn(),
 		...overrides
 	};
 }