test case 4: bootstrap

[mattsecrest]

QC Phase 4: Bootstrap Wrappers

Wrap Phase 3 methods with bootstrap inference. Verify CI construction, resampling mechanics, and convergence.

• EC_IPW_OPT_bootstrap() — IPW optimal with bootstrap
• EC_AIPW_OPT_bootstrap() — AIPW optimal with bootstrap
• DID_EC_IPW_bootstrap() — DID IPW with bootstrap
• DID_EC_AIPW_bootstrap() — DID AIPW with bootstrap
• DID_EC_OR_bootstrap() — DID outcome regression with bootstrap