[fix] JSL instruction

[smokku]

Fixes #17

[Copilot]

Pull Request Overview

This PR fixes the JSL (Jump to Subroutine Long) instruction implementation in the W65C816S CPU emulator. The changes correct the cycle timing and execution sequence to match the official W65C816S datasheet specification.

• Adjusted JSL instruction cycle timing from 9 cycles to 8 cycles
• Fixed the order of operations during JSL execution to properly handle address calculation and stack operations
• Added comprehensive test coverage for the JSL instruction

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/codegen/w65c816s_gen.py	Updates the JSL instruction generator to fix the cycle sequence and timing
src/chips/w65c816s.h	Modifies the generated JSL instruction implementation with corrected cycle behavior
src/tests/cputest.cpp	Adds new test case to verify JSL instruction works correctly

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