Add Lambda Core in Bash

[kserrec]

Summary

• add a standalone GNU Bash implementation of the Lambda Core booleans and Church numerals
• represent higher-order values with Bash function names and invoke them through quoted command expansion
• implement TRUE, FALSE, NOT, AND, OR, ZERO, SUCC, PRED, and ONE derived from SUCC ZERO
• demonstrate the complete boolean truth tables and numeral behavior at the zero boundary
• add a focused test and an expected-output baseline captured from an observed local run

The implementation requires Bash 4 or newer, uses no external runtime packages, and does not use eval or generated source code.

Testing

• bash -n languages/b/bash/lambda-core.bash
• sh -n languages/b/bash/test.sh
• sh languages/b/bash/test.sh
• sh run-tests.sh

Local harness result: PASS b/bash; 10 passed, 0 failed, 6 skipped because their toolchains are unavailable locally, and 1 pre-existing Java baseline remains pending.