Ship the per-user config, and recommend a font that exists

Two things anyone installing v0.1.0 would have hit.

The per-user files were listed in install-assets.sh as installed 'by
hand', which meant a clean machine logged in to a bare compositor with
nothing drawn on it and no binding that opened anything. They are now
installed as a skeleton under share/hyprcosmic/skel, laid out exactly as
they sit under ~/.config, and the session copies what is missing at
login. The audit still forces every file under config/ into exactly one
list, so this could not be quietly skipped again.

theme.css, theme.rasi and local.rasi are new and deliberately empty. They
are the relative @imports of style.css and config.rasi, and a missing
@import is fatal to both consumers rather than a warning they skip: GTK
fails the whole stylesheet, and rofi reports the error in place of the
launcher. Every colour they could define already has a default from
palette.css and palette.rasi, so empty is the correct content until
import-theme writes them. style.css's own header has promised 'a sibling
file we create at install time' since it was written; now there is one.

Recommends: nerd-fonts named a package that is in no Fedora repository,
so it could never be satisfied and the font never arrived -- silently,
which is what Recommends does when it cannot resolve. Fedora has no Nerd
Font at all: texlive-inconsolata-nerd-font lands under texmf-dist and
kitty's SymbolsNerdFont under /usr/lib64/kitty, and fontconfig scans
neither. Recommend font(notosansmono) instead, the fallback rules.rasi
already names, and say in the README how to install the glyphs by hand.

config/rofi/local.rasi

@@ -0,0 +1,29 @@
+/* Per-machine launcher settings for HyprCosmic.
+ *
+ * Empty until `hyprcosmic-conf import-theme --assets` writes it. It exists from
+ * the first session because config.rasi imports it, and a missing @import is an
+ * error rofi reports in place of the launcher rather than a warning it skips.
+ *
+ * It is the last of the four imports in config.rasi, so anything here wins; it
+ * is also overwritten by the next import run with --overwrite, so keep hand
+ * edits somewhere else.
+ *
+ * Two things belong in this file and nothing else does: values that name a path
+ * or a package on this particular machine, which neither /usr/share/hyprcosmic
+ * nor a HyDE theme file can know. Concretely, that is the icon theme and the
+ * sidebar image:
+ *
+ *   configuration {
+ *       icon-theme: "Tela-circle-purple", "Adwaita";
+ *   }
+ *
+ *   dummywall {
+ *       background-image: url("/home/you/.local/share/wallpapers/hyprcosmic/current", height);
+ *   }
+ *
+ * Both are shown commented out rather than set, because a default that named
+ * an icon theme nobody has installed, or a wallpaper path under someone else's
+ * home, would be worse than no default at all.
+ */
+
+* {}

config/rofi/theme.rasi

@@ -0,0 +1,16 @@
+/* Step 2 of the import chain in config.rasi: the installed HyDE theme's rofi
+ * colours.
+ *
+ * Empty on purpose, for the same reason as waybar's theme.css: a missing
+ * @import is an error rofi reports in place of the launcher rather than a
+ * warning it skips, so config.rasi can only import a file that is guaranteed
+ * to exist. palette.rasi already defines every name rules.rasi reads, so
+ * defining nothing here leaves a complete theme rather than an unresolved
+ * reference.
+ *
+ * `hyprcosmic-conf import-theme` overwrites this with the imported theme's
+ * rofi colours. Hand-written overrides belong in local.rasi, which is imported
+ * after the rules and is left alone unless --overwrite is passed.
+ */
+
+* {}

config/waybar/theme.css

@@ -0,0 +1,18 @@
+/* Step 2 of the import chain in style.css: the installed HyDE theme's
+ * waybar.theme.
+ *
+ * This copy is deliberately empty of rules. It is not a stub waiting to be
+ * written -- an empty file is the correct content when no theme has been
+ * imported, and it is what makes the other three steps work:
+ *
+ *   - A missing @import is fatal in GTK, so style.css cannot name a file that
+ *     might not exist. This one always exists, from the moment the session
+ *     first starts.
+ *   - Every colour the rules consume already has a default from palette.css
+ *     and bridge-hyde.css, so a file that defines nothing leaves a complete
+ *     stylesheet rather than an undefined name.
+ *
+ * `hyprcosmic-conf import-theme` overwrites this with the waybar.theme of the
+ * theme being imported. Anything written here by hand is lost at that point,
+ * which is why the per-user override belongs in style.css instead.
+ */