Build transcript-based tutorial documentation system (#80)

* Add Video Transcript summarization template

Added a new built-in template optimized for video tutorial transcripts:
- Captures step-by-step UI walkthroughs
- Documents navigation paths and UI elements
- Includes prerequisites, expected results, and troubleshooting
- Perfect for tutorial content describing how to use applications/websites

* Fix: Auto-refresh tree view after saving summaries to Inbox

When summaries are saved to the Inbox folder, the Notes tree view now
automatically refreshes to display the new note immediately. This fixes
the UX issue where users had to manually click refresh to see new summaries.

Changes:
- Pass NotesTreeProvider to all summarization command handlers
- Call refresh() after saving summary files to Inbox
- Update function signatures throughout summarization command chain

* Refactor: Convert summarization commands to class-based approach

Addresses code review feedback to eliminate parameter drilling by
refactoring command handlers into a SummarizationCommands class.

Changes:
- Created SummarizationCommands class with injected dependencies
- Converted public handler functions to class methods
- Moved private helpers (promptForTemplate, displaySummary, etc.) to private methods
- Updated extension.ts to instantiate class and use bound methods
- All handlers now access dependencies via this.* instead of parameters

Benefits:
- Eliminates parameter drilling across 6+ functions
- Easier to extend with new dependencies in future
- Better encapsulation and OOP principles
- Cleaner function signatures throughout

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Co-authored-by: Claude <[email protected]>

Author: jsonify