Add five popular Lambda Core implementations

[kserrec]

Adds Lambda Core implementations for the five highest-ranked absent programming and scripting languages from the Stack Overflow 2025 usage results: SQL, Bash, PowerShell, PHP, and Rust.

Each language includes Church booleans, Church numerals, self-checking examples, a README, test.sh, and an observed expected-output.txt baseline. SQL is explicitly documented as a relational SQLite emulation because SQLite has no first-class functions.

Verification:

• Repository harness: 11 passed, 0 failed, 9 unavailable local toolchains skipped, 1 pre-existing Java baseline pending
• Bash and Rust exact-baseline checks passed locally
• PHP 8.4, PowerShell 7.5, and SQLite exact-baseline checks passed in clean containers
• Shell syntax, PHP lint, Rust warnings and formatting, and diff checks passed

This combined expansion supersedes the narrower Bash PR #33 and Rust PR #36.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-30T23:51:42.557156Z	dbfcffe	PR opened

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