Adds `gog slides create-from-template` command to create presentations
from templates with automatic placeholder text replacement.
Features:
- {{key}} placeholder format (auto-wrapped)
- Multiple replacement sources: --replace flags and --replacements JSON file
- Type conversion for JSON (numbers, booleans → strings)
- --exact flag for arbitrary string replacement
- Replacement statistics in output
- JSON/text output modes
Implementation:
- Copy template via Drive API
- Batch text replacement via Slides API ReplaceAllText
- Comprehensive error handling and validation
- 7 test cases covering all features and edge cases
Usage: gog slides create-from-template <templateId> <title> \
--replace "key=value" \
--replacements data.json
Co-authored-by: Cursor <cursoragent@cursor.com>
