fix: close the tail items from the targeted re-audit

Resolves the 13 rows still partial in docs/rewrite/notes/review-rv4-
codex.md (details in final-Z5.md):
- Escaped config strings are decoded to raw bytes at every OS boundary:
  Flatpak cwd/argv to D-Bus, screen-file paths, the default config
  template, GHOSTTY_RESOURCES_DIR/TERMINFO/shell integration/
  bindtextdomain consumers, custom shader loading, list-themes hyperlinks.
- osbytes escapes literal U+FDD0 on non-Unix too (bijective everywhere);
  the GTK paste dialog only decodes text that was actually encoded.
- shadertoy: whole-array uses of iChannelTime rebuild a plain float[4]
  from the std140-padded members (naga-validated, MSL offsets checked).
- libghostty-vt: the OSC parser holds caller-allocated storage inline
  and command payloads borrow from it, so ghostty_osc_end performs no
  global allocations (verified from Rust and C).
- crash: aarch64 Linux minidump context fixed; macOS fatal signals record
  siginfo, registers and a fault-safe stack walk.
- tripwire: selectionString map allocation-failure cleanup test ported.
- libghostty-vt emits the versioned soname libghostty-vt.so.0 at build
  time (no patchelf needed at install).

Test Plan:
- cargo test --workspace (3342 passed)
- just check-macos; just check-macos x86_64-apple-darwin;
  just check-windows; just check-wasm
- cargo check --target aarch64-unknown-linux-gnu -p ghostty-crash

Cargo.lock

@@ -1496,6 +1496,7 @@ dependencies = [
  "ghostty-os",
  "libc",
  "log",
+ "mach2",
  "minidump",
  "minidump-writer",
  "serde_json",