Overhaul the Intel 4004 instruction set to match the real opcode map,
adding missing instructions (NOP, FIM, FIN, JIN, ISZ, KBP, DCL, WR0-3,
RD0-3) and refining two-byte instruction handling with proper M1/M2
data phases. Rewrite the CPU fetch-execute cycle to correctly process
two-byte opcodes across separate clock cycles.
Improve Intel 4001 ROM timing with M1/M2 nibble phase tracking and an
A3 wait counter so the ROM drives data only when the CPU expects it.
Fix state-machine transition helpers in Intel 4002 and 4003 to capture
the old state before processing events, preventing incorrect exit/entry
callbacks.
Add non-propagating pin driver methods to prevent deadlocks caused by
bidirectional pin connections during signal propagation.
Add Fibonacci integration test and opcode fix plan document.
Update all README files to reflect the new instruction set.
Remove redundant/obsolete tests from intel_400x_tests.rs, retaining core test coverage for Intel400x common functionality. Apply rustfmt formatting to intel_4002.rs and state machine test files.
Changes:
- Remove ~40 redundant test functions from intel_400x_tests.rs
- Apply rustfmt formatting to intel_4002.rs
- Fix import formatting in state machine tests
- Clean up trailing whitespace
