chore(release): prepare v0.6.0-beta with whisper.cpp as default (#181)

* docs: update all documentation for whisper.cpp as default engine

Comprehensive documentation update highlighting whisper.cpp as the new
default speech recognition engine:

README.md:
- Added 'Major Change: whisper.cpp is Now Default!' section
- Updated Features to highlight whisper.cpp and Vulkan GPU support
- Updated Quick Install section with engine choices
- Changed default engine from whisper to whisper_cpp in examples
- Updated configuration examples
- Updated roadmap to mark whisper.cpp as complete

docs/INSTALL.md:
- Added whisper.cpp section with performance benefits
- Updated installation options (--engine flag)
- Added GPU support matrix and Vulkan detection info
- Added installation time comparison table
- Updated system requirements (lower disk space for whisper.cpp)

docs/USER_GUIDE.md:
- Added comprehensive 'Choosing Your Engine' section
- Added GPU acceleration information
- Updated tips to mention whisper.cpp benefits
- Added model size recommendations

web/src/app/page.tsx:
- Updated hero to mention whisper.cpp (C++ optimized, Vulkan support)
- Changed installation time from ~5-10 min to ~1-2 min
- Updated Features section to mention Vulkan GPU support
- Added whisper.cpp as default engine card (3-column layout)
- Updated installation commands (--engine flags)
- Updated FAQ about switching engines

This ensures all documentation reflects whisper.cpp as the new default
and highlights its major benefits: 10x faster install, universal GPU
support, and C++ optimized performance.

* chore(release): prepare v0.6.0-beta

This release brings whisper.cpp as the new default speech recognition engine:

Version Updates:
- Bump version from 0.5.0-beta to 0.6.0-beta
- Update src/vocalinux/version.py
- Update web/package.json

Documentation Updates:
- README.md: Update all v0.5.0-beta references to v0.6.0-beta
- docs/INSTALL.md: Update version references and installation commands
- docs/UPDATE.md: Add new 'What's New' section highlighting whisper.cpp
- SECURITY.md: Update supported versions table (0.6.x now supported)

Website Updates:
- web/src/app/layout.tsx: Update softwareVersion to 0.6.0-beta

Release Highlights:
- whisper.cpp is now the default engine (10x faster install!)
- Universal GPU support via Vulkan (AMD, Intel, NVIDIA)
- C++ optimized inference with multi-threading
- ~1-2 minute installation vs ~5-10 minutes before

Testing:
- All 472 tests passing
- Black formatting clean
- Flake8 linting clean
- isort import ordering clean

* ui(website): improve hero section layout

* docs(readme): remove duplicate What's New section

src/vocalinux/version.py

@@ -2,8 +2,8 @@
 Version information for Vocalinux.
 """
 
-__version__ = "0.5.0-beta"
-__version_info__ = (0, 5, 0, "beta")
+__version__ = "0.6.0-beta"
+__version_info__ = (0, 6, 0, "beta")
 __author__ = "Jatin K Malik"
 __email__ = "jatinkrmalik@gmail.com"
 __license__ = "GPL-3.0"