fix(email-to-todo): improve extraction and review flow

[Maximum-Prosper]

Closes #358

Changes

• Improved deterministic task extraction for the Email-to-Todo converter.
• Preserved source email IDs in task drafts when available.
• Added explicit due-date parsing for phrases like by Friday and due 2026-07-01.
• Refined title extraction so generic emails fall back to actionable body text.
• Updated docs and tests to match the isolated implementation.

Testing

• git diff --check
• Focused converter tests updated in tools/v1/individual/email-to-todo-converter/tests/emailToTodoView.test.ts

Notes

• This stays fully isolated inside tools/v1/individual/email-to-todo-converter/.
• It does not wire into the main app or shared inbox architecture.