Fix CHANGELOG: rename survey-bootstrap PR placeholder #352 to #355

CHANGELOG.md

@@ -29,12 +29,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - **`did_had_pretest_workflow(aggregate="event_study")` verdict no longer emits the "paper step 2 deferred to Phase 3 follow-up" caveat** — the joint pre-trends Stute test closes that gap. The two-period `aggregate="overall"` path retains the existing caveat since the joint variant does not apply to single-pre-period panels. Downstream code that greps verdict strings for the Phase 3 caveat will see it suppressed on the event-study path.
-- **SyntheticDiD bootstrap no longer supports survey designs** (capability regression in PR #351, **restored in PR #352** — see Added/Changed entries directly below). The removed fixed-weight bootstrap path was the only SDID variance method that supported strata/PSU/FPC (via Rao-Wu rescaled bootstrap); the PR #351 paper-faithful refit bootstrap initially rejected all survey designs (including pweight-only) with `NotImplementedError`. PR #352 restores the capability via a weighted-FW + Rao-Wu composition; the lock-out window applies only to the v3.2.x line that ships PR #351 alone (without PR #352). Composing Rao-Wu rescaled weights with Frank-Wolfe re-estimation: see `docs/methodology/REGISTRY.md` §SyntheticDiD `Note (survey + bootstrap composition)`.
+- **SyntheticDiD bootstrap no longer supports survey designs** (capability regression in PR #351, **restored in PR #355** — see Added/Changed entries directly below). The removed fixed-weight bootstrap path was the only SDID variance method that supported strata/PSU/FPC (via Rao-Wu rescaled bootstrap); the PR #351 paper-faithful refit bootstrap initially rejected all survey designs (including pweight-only) with `NotImplementedError`. PR #355 restores the capability via a weighted-FW + Rao-Wu composition; the lock-out window applies only to the v3.2.x line that ships PR #351 alone (without PR #355). Composing Rao-Wu rescaled weights with Frank-Wolfe re-estimation: see `docs/methodology/REGISTRY.md` §SyntheticDiD `Note (survey + bootstrap composition)`.
 
-### Added (PR #352)
+### Added (PR #355)
 - **SDID `variance_method="bootstrap"` survey support restored** via a hybrid pairs-bootstrap + Rao-Wu rescaling composed with a weighted Frank-Wolfe kernel. Each bootstrap draw first performs the unit-level pairs-bootstrap resampling specified by Arkhangelsky et al. (2021) Algorithm 2 (`boot_idx = rng.choice(n_total)`), and *then* applies Rao-Wu rescaled per-unit weights (Rao & Wu 1988) sliced over the resampled units — NOT a standalone Rao-Wu bootstrap. New Rust kernel `sc_weight_fw_weighted` (and `_with_convergence` sibling) accepts a per-coordinate `reg_weights` argument so the FW objective becomes `min ||A·ω - b||² + ζ²·Σ_j reg_w[j]·ω[j]²`. New Python helpers `compute_sdid_unit_weights_survey` and `compute_time_weights_survey` thread per-control survey weights through the two-pass sparsify-refit dispatcher (column-scaling Y by `rw` for the loss, `reg_weights=rw` for the penalty on the unit-weights side; weighted column-centering + row-scaling Y by `sqrt(rw)` for the loss with uniform reg on the time-weights side). `_bootstrap_se` survey branch composes the per-draw `rw` (Rao-Wu rescaling for full designs, constant `w_control` for pweight-only fits) with the weighted-FW helpers, then composes `ω_eff = rw·ω/Σ(rw·ω)` for the SDID estimator. Coverage MC artifact extended with a `stratified_survey` DGP (BRFSS-style: N=40, strata=2, PSU=2/stratum); the bootstrap row's near-nominal calibration is the validation gate (target rejection ∈ [0.02, 0.10] at α=0.05). New regression tests across `test_methodology_sdid.py::TestBootstrapSE` (single-PSU short-circuit, full-design and pweight-only succeeds-tests, zero-treated-mass retry, deterministic Rao-Wu × boot_idx slice) and `test_survey_phase5.py::TestSyntheticDiDSurvey` (full-design ↔ pweight-only SE differs assertion). See REGISTRY.md §SyntheticDiD ``Note (survey + bootstrap composition)`` for the full objective and the argmin-set caveat.
 
-### Changed (PR #352)
+### Changed (PR #355)
 - **SDID bootstrap SE values under survey fits now differ numerically from the v3.2.x line that shipped PR #351 alone**: the fit no longer raises `NotImplementedError`, and instead returns the weighted-FW + Rao-Wu SE. Non-survey fits are unaffected (the bootstrap dispatcher routes only the survey branch through the new `_survey` helpers; non-survey fits continue to call the existing `compute_sdid_unit_weights` / `compute_time_weights` and stay bit-identical at rel=1e-14 on the `_BASELINE["bootstrap"]` regression). SDID's `placebo` and `jackknife` paths still reject `strata/PSU/FPC` (separate methodology gap; tracked in TODO.md as a follow-up PR).
 
 ## [3.2.0] - 2026-04-19