Issue 1: Fix recurrence calculation for overdue tasks
- Use completion date (End) as base for next instance, not original due date
- If task due Monday completed Wednesday, next is Wednesday+7d not Monday+7d
- Fallback to Due date if End is not set
- Update test to verify new behavior
Issue 2: Fix description parsing to work without quotes
- Add parseAddArgs() to extract description from non-modifier words
- Description = all words that don't start with +, -, or contain :
- Enables: opal add buy groceries +shop carrots → 'buy groceries carrots'
- Validate description is required (error if only modifiers)
- Validate recurring tasks require due date
Issue 3: Implement flexible command syntax
- Add preprocessArgs() to parse arguments before Cobra routing
- Detect command position and split filters (left) from modifiers (right)
- Rewrite os.Args so Cobra routes correctly
- Enable both 'opal 2 done' and 'opal done 2' syntax
- Commands without modifiers accept filters on either side
- Commands with modifiers enforce [filters] command [modifiers]
- Add confirmation for modify without filters (modifies all tasks)
All commands updated to use preprocessed ParsedArgs from context.
All tests passing (33 tests).
- Complete SpawnNextInstance() for creating recurring task instances
- Implement automatic next instance spawning on task completion
- Add support for 'until' date to expire recurrences
- Copy tags from template to new instances
- Add comprehensive recurrence tests (6 tests, all passing)
- Test pattern parsing, formatting, next due calculation
- Test end-to-end recurring task workflow
- Test expiration with until dates