format_ae_listing(): AE duration set to NA (not "Unknown") for outcomes outside two hardcoded values

The bug is in R/ae_listing.R around lines 394-402 in the format_ae_listing() function. First, read the function to understand how ADURN and AEOUT are used. Then, create a small test to reproduce the issue with the provided examples. The fix is to replace the charmatch() calls with an exact membership test using %in%. After making the change, run any existing tests for this function to ensure the fix works and doesn't break other behavior.

When ADURN is missing, format_ae_listing() derives the Duration value from AEOUT (R/ae_listing.R, around lines 394-402):

na_dur <- is.na(res[["ADURN"]])
if (any(na_dur)) {
  aeout_na <- toupper(res[["AEOUT"]][na_dur])
  res[["Duration"]][na_dur] <- ifelse(
    charmatch(aeout_na, "RECOVERING/RESOLVING") > 0 |
      charmatch(aeout_na, "NOT RECOVERED/NOT RESOLVED") > 0,
    "Continuing", "Unknown"
  )
}

Two problems with charmatch() here:

1. NA leaks into the result. charmatch(x, table) returns NA when x matches nothing in table. For any outcome that is neither RECOVERING/RESOLVING nor NOT RECOVERED/NOT RESOLVED (e.g. FATAL, RECOVERED/RESOLVED), both charmatch() calls return NA, so the ifelse() condition is NA | NA = NA and ifelse(NA, ...) yields NA. The intended fallback "Unknown" is never reached for those rows.

2. Silent prefix matching. charmatch() does partial (prefix) matching, so charmatch("R", "RECOVERING/RESOLVING") returns 1. An exact comparison was almost certainly intended.

Reproducer:

f <- function(aeout) ifelse(
  charmatch(aeout, "RECOVERING/RESOLVING") > 0 |
    charmatch(aeout, "NOT RECOVERED/NOT RESOLVED") > 0,
  "Continuing", "Unknown")
f("FATAL")               # NA   (expected "Unknown")
f("RECOVERED/RESOLVED")  # NA   (expected "Unknown")

Suggested fix: use an exact set-membership test instead of charmatch():

res[["Duration"]][na_dur] <- ifelse(
  aeout_na %in% c("RECOVERING/RESOLVING", "NOT RECOVERED/NOT RESOLVED"),
  "Continuing", "Unknown"
)

This affects normal, valid data whenever a subject has a missing AE duration and an outcome outside the two listed categories.