fix: close remaining gaps found by the completeness audit

Addresses the partial ports listed in
docs/rewrite/notes/review-completeness-codex.md (details in
docs/rewrite/notes/gaps-X2.md):
- Flatpak: the exit watcher no longer consumes the host command; a
  shared FlatpakSignalHandle lets closing a surface still SIGHUP the
  host process group.
- Child environment is byte-preserving end to end (ghostty_os::EnvMap
  of OsStrings) and Snap paths are filtered like filterSnapPaths.
- argv handling no longer panics on non-UTF-8 arguments.
- URI percent-decoding keeps raw bytes; OSC 7 pwd is passed through
  without lossy conversion.
- Keybinding comparison/hashing uses full Unicode case folding from a
  table generated from CaseFolding.txt (Unicode 17.0.0).
- Link regexes set Oniguruma's whole-search retry limit through the new
  minimal ghostty-onig crate (one SAFETY-commented FFI call).
- OSC 9 NUL-capacity check ordering matches Zig.
- Wayland registry binds/clears globals advertised after startup.
- Custom shaders may pass sampler2D to helper functions (naga adapter).
- +list-themes preview renders OSC 8 links, styled underlines and
  follows color-scheme reports.

Also includes the inspector's integration edits in shared files
(renderer state hook, termio VT recording, core/apprt-gtk wiring), X1's
config/input/cli additions for completion generation, and a fix for a
race in the termio backpressure test (it wrote before `stty raw`
applied, so the cooked line discipline dropped bytes past MAX_CANON).

Test Plan:
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings

src/main.rs

@@ -14,7 +14,8 @@ use ghostty_cli::build_info::{self, BuildInfo, Version};
 use ghostty_core::global::{self, InitOptions};
 
 fn main() -> ExitCode {
-    let args: Vec<String> = std::env::args().collect();
+    // Byte-safe argv (`std::env::args()` panics on non-UTF-8 arguments).
+    let args: Vec<String> = ghostty_os::args::collect_lossy();
 
     // We first start by initializing our global state. This sets up
     // process-level state we need to run the terminal. We detect whether a
@@ -92,17 +93,9 @@ fn build_info() -> BuildInfo {
     let gtk = gtk_version::get_runtime_version();
     let adw = adw_version::get_runtime_version();
     BuildInfo {
-        gtk_build: Some(Version {
-            major: 4,
-            minor: 14,
-            micro: 0,
-        }),
+        gtk_build: Some(version(gtk_version::COMPTIME_VERSION)),
         gtk_runtime: Some(version((gtk.0, gtk.1, gtk.2))),
-        adw_build: Some(Version {
-            major: 1,
-            minor: 5,
-            micro: 0,
-        }),
+        adw_build: Some(version(adw_version::COMPTIME_VERSION)),
         adw_runtime: Some(version((adw.0, adw.1, adw.2))),
         ..BuildInfo::default()
     }