Return description and author for installed packages

[bricestacey]

Extend .ps.rpc.pkg_list to return description and author alongside the existing fields so Positron's Packages pane card view can render them. Both are normalized for display: descriptions collapse whitespace so multi-line text fits on one line, and author strips trailing <email> markers from Maintainer values.

All three methods (pak / base / renv) populate the new fields. base and renv share a helper that wraps utils::installed.packages() so the lib lookup only differs by lib.loc.

See posit-dev/positron#12925

[jennybc]

Some high-level thoughts:

1. It's not immediately obvious to me why a pak variant is needed when listing installed packages and perhaps enriching with some information from DESCRIPTION. My instinct is that someone choosing or accepting a pak lifestyle re: packages pane operations is really (and probably only?) about installation. I suspect this can be simplified to using something like .ps.pkg_list_installed() for pak/base/renv and just feeding the lib.loc in the renv case.
2. I'd lean more into R's native vectorization. I think there's a lot of explicit iteration that can be eliminated. I gather some sort of row-by-row move is needed eventually to get this into the needed shape, but I think we can do that all at once at the last moment. Something along these lines:

.ps.pkg_list_installed <- function(lib.loc = NULL) {
    ip <- utils::installed.packages(
        lib.loc = lib.loc,
        fields = c("Description", "Maintainer")
    )

    pkgs <- ip[, "Package"]
    vers <- ip[, "Version"]
    description <- trimws(gsub(
        "\\s+",
        " ",
        ifelse(is.na(ip[, "Description"]), "", ip[, "Description"]),
        perl = TRUE
    ))
    maintainer <- trimws(gsub(
        "\\s*<[^>]+>",
        "",
        gsub(
            "\\s+",
            " ",
            ifelse(is.na(ip[, "Maintainer"]), "", ip[, "Maintainer"]),
            perl = TRUE
        ),
        perl = TRUE
    ))
    ids <- paste0(pkgs, "-", vers)

    Map(
        function(id, pkg, ver, description, maintainer) {
            list(
                id = id,
                name = pkg,
                displayName = pkg,
                version = ver,
                description = description,
                maintainer = maintainer
            )
        },
        ids,
        pkgs,
        vers,
        description,
        maintainer
    )
}

[jennybc]

Here's a slightly cleaner version of my suggestion:

.ps.pkg_list_installed <- function(lib.loc = NULL) {
    ip <- utils::installed.packages(
        lib.loc = lib.loc,
        fields = c("Description", "Maintainer")
    )

    name <- ip[, "Package"]
    version <- ip[, "Version"]
    id <- paste0(name, "-", version)
    description <- trimws(gsub(
        "\\s+",
        " ",
        ifelse(is.na(ip[, "Description"]), "", ip[, "Description"]),
        perl = TRUE
    ))
    maintainer <- trimws(gsub(
        "\\s*<[^>]+>",
        "",
        gsub(
            "\\s+",
            " ",
            ifelse(is.na(ip[, "Maintainer"]), "", ip[, "Maintainer"]),
            perl = TRUE
        ),
        perl = TRUE
    ))

    Map(
        list,
        id = id,
        name = name,
        displayName = name,
        version = version,
        description = description,
        maintainer = maintainer
    )
}

The Map() could be even cleaner if name and displayName did not derive from the same intermediate object, i.e. we wouldn't need this = that stuff at all. Are name and displayName ever different? And if so, would that ever happen here in ark or might that be a Positron/typescript matter?