v0.3.0

CRAN (R) registry adapter — 9th ecosystem. ecosystem:"cran" resolves an R package's latest version + repo (from the CRAN URL/BugReports fields) via the crandb JSON API, feeding the same chain (e.g. dplyr → github.com/tidyverse/dplyr → dplyr.tidyverse.org/llms.txt). Turns the mechanical half of a hand-curated R docs guide into a live lookup.

No other behavior change.