tests/julia: add julia tests

[avinxshKD]

Added 181 assertions across 4 test suites for concore.jl:

• test_parser.jl: safe_parse_list (covers NumPy string wrappers, edge case floats, booleans)
• test_config.jl: port parsing, params, and maxtime fallbacks
• test_sync.jl: unchanged state tracking and initval
• test_protocol.jl: concore_read/concore_write I/O, wire format checks, and round-trips

To verify locally:
julia tests/julia/runtests.jl

[avinxshKD]

Hey @pradeeban as discussed, added unit tests for concore.jl (parser, config, sync, protocol).
Pls take a look and Let me know if you want any adjustments.