feat: add break-type masks and fix BreakCount reporting (fixes #54)

[fam007e]

Fixes #54

This PR adds the ability to disable specific Unicode break types via kbts_break_config_flags to optimize performance in per-frame UI pipelines. It also fixes a bug in break count reporting.

Summary of Changes

1. Break-Type Masks (Optimization)

• Added new flags to kbts_break_config_flags: DISABLE_DIRECTION_BREAK, DISABLE_SCRIPT_BREAK, DISABLE_GRAPHEME_BREAK, DISABLE_WORD_BREAK, and DISABLE_LINE_BREAK.
• Optimized kbts__BreakAddCodepoint to skip expensive Unicode property lookups for disabled types.
• Updated kbts__DoBreak to filter emitted flags based on the configuration.

2. Bug Fix: BreakCount Reporting

• Fixed a bug in kbts_BreakEntireString where BreakCount was only updated if the Breaks buffer was NULL. It now correctly reports the count for both dry runs and actual runs.

Verification

• Verified that BreakCount is correctly reported when providing a buffer.
• Verified that disabling specific break types successfully suppresses the corresponding flags in the output.
• Verified that the system remains stable when optional break types are disabled (mandatory paragraph direction is preserved).