EventStudy 0.65.0 — Polish

EventStudy v0.65.0 — Polish

The Polish milestone: brand identity (logo/hex/favicons/OG, ecosystem-aligned
pkgdown theme, stable badge), plot aesthetics (theme_eventstudy() +
colorblind-safe es_colours), report aesthetics (tinytable tables, captioned
figures, per-format sizing, HTML report.css), API & message polish (invisible(x)
prints, format.* methods, classed eventstudy_* conditions, verbose= quiet mode),
and docs & site (@family/@Seealso cross-links, README Ecosystem section,
check_pkgdown() in CI, tightened getting-started vignette).

Purely additive — no statistical-correctness or valid-input behavior change.
Audit PASSED 30/30 reqs, 5/5 phases; suite green 2359/0; 0 new CRAN findings.