feat-deviant(os): embed a configurable resource directory

Relocating a Cargo-installed binary loses executable-relative resource
lookup even when themes and shell integration exist under /usr/share.
Allow packagers to set GHOSTTY_BUILD_RESOURCES_DIR when compiling.

Absolute paths are used directly; relative paths resolve against the
running executable's directory for relocatable installations. Explicit
paths do not require terminfo sentinels. A nonempty runtime override wins
in every profile when the build option is configured. Unset or empty
build options preserve existing discovery, including debug precedence.
Cargo watches the build option so changing or unsetting it recompiles
lookup. Resource files still need to be installed separately.

Document this requested upstream deviation and the build option in the
README, architecture overview, and deviation register.

Test Plan:
- Eight resource lookup unit tests pass.
- Nightly formatting and ghostty-os Clippy with -D warnings pass.
- Production build with /usr/share/ghostty succeeds; a copied executable
  lists all 463 themes with no runtime override.
- Compiled probes verify absolute, relative, unset, and empty options,
  Cargo rebuilds, relocation, runtime overrides, and unrelated cwd.

Deviation-Register: docs/rewrite/DEVIANT_FIXES.md

docs/rewrite/ARCHITECTURE.md

@@ -70,6 +70,14 @@ ghostty-bench (benchmarks), ghostty-build-data (completions, man pages, syntax).
 Non-code: `resources/` (shell-integration, themes, terminfo), `dist/` (desktop
 integration), `po/` (translations), crate-local `res/`/`shaders/`/`resources/`.
 
+Resource lookup: `ghostty-os::resourcesdir` accepts the optional build-time
+`GHOSTTY_BUILD_RESOURCES_DIR` path (watched by `ghostty-os/build.rs`). Runtime
+`GHOSTTY_RESOURCES_DIR` overrides a configured build path; otherwise that path
+precedes automatic discovery. Relative build paths resolve from the executable's
+directory, allowing relocatable installations. Without a build path, upstream's
+environment/terminfo lookup and the checkout resource fallback apply. See
+`README.md` (Build-time resource directory) and `DEVIANT_FIXES.md`.
+
 Build inputs: `ghostty-build-info/build.rs` derives version metadata from the
 workspace manifest and Git HEAD/refs, watching `packed-refs` only when it exists
 (packing loose refs also changes the watched `refs` directory). The GTK build

docs/rewrite/DEVIANT_FIXES.md

@@ -83,7 +83,7 @@ the port matches Ghostty.
 - Windows: no file locking in the ssh-cache `DiskCache` (Zig does not lock on Windows either).
 - Config theme-name basename and numeric parsing follow Zig 0.15.2, not 0.16 (`fix(config)` commits 3068e3a, a57ff41).
 
-## Other deliberate deviations (platform/Rust-imposed or out of scope)
+## Other deliberate deviations (platform/Rust-imposed or explicitly requested)
 
 Only entries with an observable behavioural difference are listed.
 
@@ -105,7 +105,8 @@ Only entries with an observable behavioural difference are listed.
 | OSC 52 base64 acceptance | Surface.zig:2149,2163 rules | Was different in both directions (Codex core audit); fixed to match Zig | `notes/review-core-codex.md` | 2f58f02 |
 | Benchmark / synthetic tooling extensions | `ghostty-bench` has no `--time` option and only the simplified terminal handler; `ghostty-synthetic` has the actions `ascii`, `osc`, `utf8` | `ghostty-bench --time` prints the measured step time to stderr; `ghostty-bench --handler=full` runs the full `stream_readonly` handler instead of the print-only one; `ghostty-synthetic +sgr` generates SGR-heavy output. Dev/benchmark tooling only; otherwise upstream behaviour is unchanged | `crates/ghostty-bench/src/main.rs`, `src/benches.rs`, `src/bin/ghostty-synthetic.rs`; `notes/review-rv16-codex.md` | 0c4f0ee |
 | Inspector font rasterizer (Windows, Apple, wasm) | Dear ImGui is built with `IMGUI_ENABLE_FREETYPE` (`pkg/dcimgui`), so the 32 px inspector font is rasterized by FreeType | Linux and other Unix targets: FreeType (`dear-imgui-rs` feature `freetype`, system FreeType through pkg-config), 32 px. Windows, Apple and wasm32 keep Dear ImGui's stb_truetype loader at 32 px, because `dear-imgui-sys` can only locate FreeType through pkg-config/vcpkg and those targets cannot be built or run here. Glyph anti-aliasing differs slightly there. | `crates/ghostty-inspector/Cargo.toml`, `src/inspector.rs` (`embedded_font_source`) | Z20 (uncommitted) |
-| Development resources fallback | `resourcesDir` returns nothing when no terminfo bundle is found next to the binary | In the Cargo `dev` profile, if neither installed resources nor `GHOSTTY_RESOURCES_DIR` apply, the in-repo `<workspace>/resources` directory is used when the binary lives inside this workspace | `crates/ghostty-os/src/resourcesdir.rs` (`dev_resources_dir`) | 967e3a1 |
+| Build-time resource directory | No build-time resource path; relocated binaries need executable-relative terminfo detection or the runtime environment override | Optional `GHOSTTY_BUILD_RESOURCES_DIR` embeds an absolute path or a path relative to the executable directory. A nonempty runtime override wins in every profile when configured, then the build path; unset/empty retains existing discovery. No terminfo sentinel is required for an explicit path. User-requested packaging extension. | `crates/ghostty-os/src/resourcesdir.rs`, `crates/ghostty-os/build.rs`; tests `configured_absolute_dir_overrides_discovery_without_requiring_exe`, `configured_relative_dir_is_relative_to_executable`, `runtime_env_overrides_configured_dir_in_every_profile` | This commit (feat-deviant(os): embed a configurable resource directory) |
+| Development resources fallback | `resourcesDir` returns nothing when no terminfo bundle is found next to the binary | In any Cargo profile, if neither installed resources nor `GHOSTTY_RESOURCES_DIR` apply, the in-repo `<workspace>/resources` directory is used when the binary lives inside this workspace | `crates/ghostty-os/src/resourcesdir.rs` (`dev_resources_dir`) | 967e3a1 |
 
 ## Maintenance