Changes in version 0.1.0                        

First release. An end-to-end toolkit for shift-share (Bartik)
instrumental variables, spanning both identification routes (exogenous
shares and exogenous shocks) from instrument construction through
estimation, inference, and credibility diagnostics.

  - Estimation: ssb_design(), ssbartik(), and ssb_estimate(), reporting
    a panel of confidence intervals (IID, EHW, and exposure-robust AKM /
    AKM0 by default; cluster and two-way available on request).
  - Rotemberg / GPSS diagnostics: ssb_rotemberg(), ssb_weight_summary(),
    ssb_loo(), ssb_drop_top().
  - Shock-level (Borusyak-Hull-Jaravel) tools: ssb_aggregate(),
    ssb_shock_iv(), ssb_equivalence(), ssb_recenter().
  - Credibility checks: ssb_first_stage(), ssb_overid(),
    ssb_share_balance(), ssb_shock_balance(), ssb_pretrend(),
    ssb_placebo(), ssb_ri().
  - Output: autoplot() / ssb_plot_*() figures (including the
    ssb_plot_ci() interval comparison), and paste-ready tables via
    format(x, "latex" / "markdown") and a rendered plot() for the
    Rotemberg table.