Replace bare backticks with cli inline markup across all messaging calls

- {.arg} for argument names in stop_/warning_/message_ calls
- {.cls} after "of class" text in format_class() and elsewhere
- {.fun} for function names (replaces `fn()` pattern)
- {.pkg} for tidyverse package names (dplyr, ggplot2)
- {.code} for code literals (TRUE, FALSE, expressions)
- Rewrite print.ab: use cli named-vector with * bullets and code
  highlighting when cli >= 3.0.0; keep plain-text fallback otherwise
- Fix typo in as.sir(): "of must be" -> "or must be"
- switch sir.R verbose notes from message() to message_()

https://claude.ai/code/session_01XHWLohiSTdZvCutwD7ag2b

R/custom_microorganisms.R

@@ -128,7 +128,7 @@
 #' }
 add_custom_microorganisms <- function(x) {
   meet_criteria(x, allow_class = "data.frame")
-  stop_ifnot("genus" %in% tolower(colnames(x)), paste0("`x` must contain column 'genus'."))
+  stop_ifnot("genus" %in% tolower(colnames(x)), "{.arg x} must contain column 'genus'.")
 
   add_MO_lookup_to_AMR_env()