[codex] Configure canonical TaskNote path generation

[johnyoonh]

Summary

This PR fixes inline TaskNote conversion when a task already contains a canonical [[...|note]] link, then adds configuration for the generated canonical path style.

What changed

• Use existing canonical [[...|note]] links as the target TaskNote path during inline conversion.
• Preserve the existing checkbox/task title during NLP parsing, while still allowing NLP to enrich metadata.
• Add an existing-TaskNote conflict setting for inline conversion: ask, reuse existing path, or create a unique copy.
• Add an ask-with-diff modal so users can choose whether to keep existing or incoming metadata/body content.
• Add configurable title-derived filename styles, including lowercase snake_case slugs.
• Add configurable TaskForge/source-list folder styling, including Title Case folders.
• Configure the test vault for lowercase snake_case filenames and Title Case source folders.

Why

Previously, canonical inline links could be ignored or regenerated from parsed/NLP text, which produced incorrect paths such as skill review duration.md from Monthly skill review. When the expected file already existed, conversion could fail with File already exists or create a duplicate path instead of offering a deliberate reuse path.

Validation

• npm test -- --runTestsByPath tests/unit/utils/taskTitleFormatter.test.ts tests/unit/utils/filenameGenerator.title-style.test.ts tests/unit/services/InstantTaskConvertService.test.ts tests/unit/services/TaskService.test.ts
• npm run typecheck
• npm run build:test
• /Applications/Obsidian.app/Contents/MacOS/obsidian-cli plugin:reload id=tasknotes vault=test
• /Applications/Obsidian.app/Contents/MacOS/obsidian-cli dev:errors vault=test

dev:errors only reported the pre-existing indexing error for 99_meta/reminders/lists/automation.md.