pvisim: parameters, simulator, claims records, tests; calibration of all worlds to Medicare targets

- latent-severity DGP with physicians (skill, style), policies A/B1/B2/sequential, common random numbers
- sharp null exact at the patient level (tested)
- 01_calibrate.R: joint logit-scale update; all worlds match early PVI 3.2%, late PVI 22.5/3.6%, CLTI 7.8%, death 35%
- W4 deferral target 15% (trial-like crossover); post-CLTI PVI lowered so late PVI is mostly elective

Co-Authored-By: Claude Opus 5.5 <[email protected]>

pvisim/DESCRIPTION

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+Package: pvisim
+Title: Known-Truth Simulator for Target Trial Emulation of Early Peripheral Vascular Intervention
+Version: 0.1.0
+Authors@R: person("Chen", "Dun", email = "[email protected]", role = c("aut", "cre"))
+Description: Data-generating process (claudicants nested in physicians, latent
+    severity, physician skill and style), truths by simulating interventions,
+    target trial emulation designs (naive, landmark, sequential trials,
+    clone-censor-weight), simulated RCTs, physician-level variants, negative
+    controls and performance metrics. Not for CRAN.
+License: MIT
+Encoding: UTF-8
+Depends: R (>= 4.3)
+Imports:
+    stats,
+    utils,
+    yaml,
+    data.table
+Suggests:
+    testthat (>= 3.0.0),
+    fastglm,
+    sandwich,
+    glmmTMB,
+    pkgload
+Config/testthat/edition: 3