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

crates/ghostty-input/src/binding/action.rs

@@ -1438,7 +1438,6 @@ Valid arguments are:
 
     Adjust the selection to the beginning or the end of the line
     respectively.
-
 "##
             }
             ActionKey::JumpToPrompt => {
@@ -1469,7 +1468,6 @@ Valid actions are:
 
     The default OS editor is determined by using `open` on macOS
     and `xdg-open` on Linux.
-
 "##
             }
             ActionKey::WriteScreenFile => {
@@ -1576,7 +1574,6 @@ Valid arguments:
     Creates a new split along the larger direction.
     For example, if the parent split is currently wider than it is tall,
     then a left-right split would be created, and vice versa.
-
 "##
             }
             ActionKey::GotoSplit => {
@@ -1943,7 +1940,6 @@ The value determines the crash location:
   - `render`
 
     Crash on the render thread for the focused surface.
-
 "##
             }
         }