Fix ggplot2 imports and polish utility functions for publication

Blocking issue #1: Replace all ggplot2::function() calls with bare
references in R/colors.R, R/logo.R, R/theme.R. The package already has
import(ggplot2) in NAMESPACE which makes these available directly; the ::
prefixes were triggering R CMD check 'undefined global function' NOTEs for
~30+ unimported symbols (element_line, element_rect, theme_grey, margin,
rel, unit, discrete_scale, etc.).

Suggestion #6: Replace class(x) == "character" with "character" %in% class(x)
in R/db.R (countCleanr and simpleCap). The == pattern breaks on S3 objects
with multiple class attributes.

Suggestion #7: Vectorise simpleCap() to handle multi-element input correctly.
Previously strsplit(x, ' ')[[1]] only processed the first element; now uses
vapply() to capitalise each vector element independently.

Suggestion #9: Convert match_test() from raw cat() calls to structured
writeLines() output with proper formatting and spacing between sections.

R/colors.R

@@ -199,7 +199,7 @@ civilytics_palette <- function(name = "qual", n = NULL, reverse = FALSE) {
 #' Civilytics palette function (closure)
 #'
 #' Returns a closure `function(n)` suitable for passing to
-#' [ggplot2::discrete_scale()] or similar scale constructors.
+#' [discrete_scale()] or similar scale constructors.
 #'
 #' @param name Character. Palette name. See `names(civilytics_palettes)`.
 #' @param reverse Logical. Reverse the palette order. Default `FALSE`.
@@ -221,7 +221,7 @@ civilytics_pal <- function(name = "qual", reverse = FALSE) {
 #'
 #' @param palette Character. Palette name. Defaults to `"qual"`.
 #' @param discrete Logical. `TRUE` (default) for categorical data; `FALSE`
-#'   for a continuous gradient via [ggplot2::scale_color_gradientn()].
+#'   for a continuous gradient via [scale_color_gradientn()].
 #' @param reverse Logical. Reverse the palette order. Default `FALSE`.
 #' @param ... Additional arguments passed to the ggplot2 scale function.
 #'
@@ -240,14 +240,14 @@ civilytics_pal <- function(name = "qual", reverse = FALSE) {
 scale_color_civilytics <- function(palette = "qual", discrete = TRUE,
                                    reverse = FALSE, ...) {
   if (discrete) {
-    ggplot2::discrete_scale(
+    discrete_scale(
       "colour",
       palette = civilytics_pal(palette, reverse = reverse),
       ...
     )
   } else {
     pal <- civilytics_palette(palette, reverse = reverse)
-    ggplot2::scale_color_gradientn(
+    scale_color_gradientn(
       colours = grDevices::colorRampPalette(pal)(256),
       ...
     )
@@ -261,7 +261,7 @@ scale_color_civilytics <- function(palette = "qual", discrete = TRUE,
 #'
 #' @param palette Character. Palette name. Defaults to `"qual"`.
 #' @param discrete Logical. `TRUE` (default) for categorical data; `FALSE`
-#'   for a continuous gradient via [ggplot2::scale_fill_gradientn()].
+#'   for a continuous gradient via [scale_fill_gradientn()].
 #' @param reverse Logical. Reverse the palette order. Default `FALSE`.
 #' @param ... Additional arguments passed to the ggplot2 scale function.
 #'
@@ -280,14 +280,14 @@ scale_color_civilytics <- function(palette = "qual", discrete = TRUE,
 scale_fill_civilytics <- function(palette = "qual", discrete = TRUE,
                                   reverse = FALSE, ...) {
   if (discrete) {
-    ggplot2::discrete_scale(
+    discrete_scale(
       "fill",
       palette = civilytics_pal(palette, reverse = reverse),
       ...
     )
   } else {
     pal <- civilytics_palette(palette, reverse = reverse)
-    ggplot2::scale_fill_gradientn(
+    scale_fill_gradientn(
       colours = grDevices::colorRampPalette(pal)(256),
       ...
     )