feat: fix-yaml-frontmatter-escaping — escape special characters in YAML frontmatter strings

[avoidwork]

Description

Fixes YAML frontmatter string escaping in src/memory/writer.js. The writeMemoryFile function now properly escapes backslashes, double quotes, and newlines in string values to prevent malformed YAML output when titles or frontmatter fields contain special characters.

Type of Change

• Bugfix (non-breaking change which fixes an issue)

Testing

• Updated buildMemoryContent test helper in tests/unit/memory.test.js to mirror the escaping logic
• Added unit tests for strings containing double quotes, backslashes, and newlines
• All existing tests continue to pass

Coverage

• 100% line coverage maintained

Checklist

• npm run lint passes
• Tests pass with 100% line coverage
• No forbidden patterns used
• Conventional Commit style applied

[avoidwork]

Implementation Audit Results

Change: fix-yaml-frontmatter-escaping

Goal Fulfillment: ✅ All goals met

• Goal 1: Add escapeYamlString() helper — ✅ Implemented in src/memory/writer.js
• Goal 2: Apply escaping to title field — ✅ Applied on line 27
• Goal 3: Apply escaping to string frontmatter values — ✅ Applied on line 31
• Goal 4: Update test helper — ✅ buildMemoryContent updated in tests/unit/memory.test.js
• Goal 5: Add unit tests — ✅ 4 new tests added (quotes, backslashes, newlines, frontmatter)

Spec Compliance: ✅ Matches requirements

• Modified requirement in specs/memory-system/spec.md for proper YAML escaping
• escapeYamlString escapes backslashes → double quotes → newlines in correct order
• All scenarios from the spec are covered by tests

Task Completion: ✅ All 11 tasks completed

• 1.1-1.3: Implementation complete
• 2.1-2.5: Test updates complete
• 3.1: Tests pass (1149 pass, 0 fail, 1 skipped)
• 3.2: Lint passes (0 warnings, 0 errors)
• 3.3: Application starts (TUI error is expected in non-TTY environment)

Quality Check: ✅ No issues found

• Escape order is correct (backslashes first, then quotes, then newlines)
• Helper is internal (not exported) — clean encapsulation
• Test helper mirrors production logic exactly
• New tests cover all special character edge cases
• No forbidden patterns used
• Conventional commit style applied

Notes

• npm start shows "Raw mode not supported" error — this is expected when running Ink TUI in a piped/non-TTY environment. Not a regression.