refactor: resolve cross-crate integration TODOs and resources discovery

Cleanup pass over items collected in docs/rewrite/INTEGRATION_TODO.md:
- OSC 133 printf-q / percent decoders live once in
  ghostty_vt::string_encoding; ghostty-os re-exports them.
- CursorStyle and clipboard codepoint map entries have one definition
  (ghostty-terminal); ghostty-config now depends on ghostty-terminal.
- ActionKey::docs() trailing blank lines fixed at the source; cli's
  workaround removed (+list-actions --docs still byte-identical).
- x11_color exposes names in original case; cli no longer re-parses
  rgb.txt.
- One cgroup scope wait loop (ghostty_os::cgroup::wait_for_scope).
- Flatpak passwd lookup implemented in ghostty-os via a local pty.
- +version shows the rustc version captured at build time.

Resources: dev builds find <workspace>/resources automatically (keeping
Ghostty's sentinel-file detection and GHOSTTY_RESOURCES_DIR);
scripts/gen-terminfo.sh (just terminfo) regenerates the compiled
terminfo; `just install [PREFIX]` installs binary, share/ghostty,
terminfo, desktop/D-Bus/systemd/metainfo files and icons.

Test Plan:
- cargo test for vt, os, config, input, cli
- diff `+list-keybinds`, `+list-actions --docs`, `+show-config --default`
  against /usr/bin/ghostty

justfile

@@ -33,3 +33,39 @@ test:
 
 clean:
     cargo clean
+
+# Install bin + share/ghostty (shell-integration, themes) + share/terminfo +
+# desktop file, D-Bus/systemd/metainfo and icons, mirroring Ghostty's
+# GhosttyResources.zig. Usage: `just install /usr/local` (default PREFIX
+# /usr/local; honours DESTDIR). Builds the release profile.
+install PREFIX="/usr/local": build-release
+    #!/usr/bin/env bash
+    set -euo pipefail
+    P="${DESTDIR:-}{{ PREFIX }}"
+    install -Dm755 target/release/ghostty "$P/bin/ghostty"
+    mkdir -p "$P/share/ghostty" "$P/share/terminfo"
+    cp -R resources/shell-integration resources/themes "$P/share/ghostty/"
+    find "$P/share/ghostty/shell-integration" -name '*.md' -delete
+    find "$P/share/ghostty/themes" -name '*.md' -delete
+    cp -R resources/terminfo/. "$P/share/terminfo/"
+    gen() { # template out
+        mkdir -p "$(dirname "$2")"
+        sed -e 's|@NAME@|Ghostty|g' -e 's|@APPID@|com.mitchellh.ghostty|g' \
+            -e "s|@GHOSTTY@|{{ PREFIX }}/bin/ghostty|g" "$1" > "$2"
+    }
+    gen dist/linux/app.desktop.in "$P/share/applications/com.mitchellh.ghostty.desktop"
+    gen dist/linux/dbus.service.in "$P/share/dbus-1/services/com.mitchellh.ghostty.service"
+    gen dist/linux/systemd.service.in "$P/share/systemd/user/app-com.mitchellh.ghostty.service"
+    gen dist/linux/com.mitchellh.ghostty.metainfo.xml.in "$P/share/metainfo/com.mitchellh.ghostty.metainfo.xml"
+    install -Dm644 dist/linux/ghostty_dolphin.desktop "$P/share/kio/servicemenus/com.mitchellh.ghostty.desktop"
+    install -Dm755 dist/linux/ghostty_nautilus.py "$P/share/nautilus-python/extensions/ghostty.py"
+    ic="$P/share/icons/hicolor"
+    for pair in 16:16x16 32:32x32 128:128x128 256:256x256 512:512x512 1024:1024x1024 \
+                32:16x16@2 64:32x32@2 256:128x128@2 512:256x256@2; do
+        install -Dm644 "dist/icons/${pair%%:*}.png" "$ic/${pair##*:}/apps/com.mitchellh.ghostty.png"
+    done
+    echo "installed to $P"
+
+# Regenerate resources/terminfo from the terminfo source in ghostty-termio.
+terminfo:
+    scripts/gen-terminfo.sh