feat(terminal): replace ghostty-web with an in-repo libghostty-vt adapter

The terminal ran on the ghostty-web npm package plus a hand-written patch,
and every rendering bug (recycled rows, duplicated reflow fragments, prompt
artifacts) had to be worked around from outside. The emulator now is the
official libghostty-vt C ABI compiled to WebAssembly, driven by a browser
adapter ported from T3 Code (MIT, notice in LICENSE-T3CODE) and owned in
packages/ui/src/lib/ghostty. The artifact is reproducible with
scripts/build-libghostty-wasm.sh, including a workaround for Zig 0.15.2 on
macOS 27 SDKs.

On top of the port: one WASM instance per page with every tab kept mounted
and hidden tabs paused; history replayed at the PTY size it was drawn for;
shells spawned only after the first fitted grid so zsh never prints the
PROMPT_SP marker; box drawing, block elements and Powerline arrows drawn
procedurally to the exact cell so TUI borders and block logos have no gaps
between rows; a software-rasterized canvas so Gecko renders every tab's text
with the same smoothing; the symbols-only Nerd Font bundled instead of a CDN
fetch; touch selection and scrolling driven through the surface API; a copy
button in the tab strip for touch hosts; localized aria labels.

Testing: bun tests run the real WASM (reflow, palette, replay isolation,
recycled rows, box glyph geometry); viewport and view tests use a surface
double; verified in Chromium and Zen (windowed and headless) for crisp text,
new tabs, panel reopen, resize and box glyph rendering; package type-check,
oxlint/eslint on new files, web build.

bun.lock

@@ -47,7 +47,6 @@
         "clsx": "^2.1.1",
         "cmdk": "^1.1.1",
         "express": "^5.1.0",
-        "ghostty-web": "0.4.0-next.20.g1858a59",
         "http-proxy-middleware": "^3.0.5",
         "next-themes": "^0.4.6",
         "node-pty": "1.2.0-beta.12",
@@ -185,7 +184,6 @@
         "express": "^5.1.0",
         "fflate": "^0.8.3",
         "fuse.js": "^7.1.0",
-        "ghostty-web": "0.4.0-next.20.g1858a59",
         "heic2any": "^0.0.4",
         "html-to-image": "^1.11.13",
         "http-proxy-middleware": "^3.0.5",
@@ -323,7 +321,6 @@
         "eslint": "^9.33.0",
         "eslint-plugin-react-hooks": "^5.2.0",
         "eslint-plugin-react-refresh": "^0.5.0",
-        "ghostty-web": "0.4.0-next.20.g1858a59",
         "globals": "^16.3.0",
         "next-themes": "^0.4.6",
         "nodemon": "^3.1.7",
@@ -2122,8 +2119,6 @@
 
     "get-tsconfig": ["get-tsconfig@4.13.6", "", { "dependencies": { "resolve-pkg-maps": "^1.0.0" } }, "sha512-shZT/QMiSHc/YBLxxOkMtgSid5HFoauqCE3/exfsEcwg1WkeqjG+V40yBbBrsD+jW2HDXcs28xOfcbm2jI8Ddw=="],
 
-    "ghostty-web": ["ghostty-web@0.4.0-next.20.g1858a59", "", {}, "sha512-NXA9H3IJlx+DGJukXbOPQWFkigYdAatTqkoIvM8tvhfbaYoDf3gGKxXLLyXtLYOBt5qzGdEZa294TU36gULjVg=="],
-
     "github-from-package": ["github-from-package@0.0.0", "", {}, "sha512-SyHy3T1v2NUXn29OsWdxmK6RwHD+vkj3v8en8AOBZ1wBQ/hCAQ5bAQTD02kW4W9tUp/3Qh6J8r9EvntiyCmOOw=="],
 
     "glob": ["glob@11.1.0", "", { "dependencies": { "foreground-child": "^3.3.1", "jackspeak": "^4.1.1", "minimatch": "^10.1.1", "minipass": "^7.1.2", "package-json-from-dist": "^1.0.0", "path-scurry": "^2.0.0" }, "bin": { "glob": "dist/esm/bin.mjs" } }, "sha512-vuNwKSaKiqm7g0THUBu2x7ckSs3XJLXE+2ssL7/MfTGPLLcrJQ/4Uq1CjPTtO5cCIiRxqvN6Twy1qOwhL0Xjcw=="],