chore: package the goose binary in the goose2 tauri app (#8615)

Co-authored-by: Lifei Zhou <lifei@squareup.com>

ui/goose2/README.md

@@ -8,14 +8,12 @@ Goose2 is a Tauri 2 + React 19 desktop app.
    bash/zsh: `source ./bin/activate-hermit`
    fish: `source ./bin/activate-hermit.fish`
 2. Install git hooks: `lefthook install`
-3. Install dependencies: `just setup`
+3. Prepare workspace dependencies: `just setup`
 4. Start the app: `just dev`
 
 `just clean` removes Rust build artifacts, `dist`, and `node_modules`. Run `just setup` again before `just dev`.
 
-`just setup` bootstraps a shared managed goose checkout in a home-level cache directory when it does not exist, fast-forwards it, builds a local `goose` binary, and stamps the exact branch/commit it used. `just dev` only does a lightweight preflight against that shared stamp; if the managed checkout is missing, stale, or built from the wrong branch, it warns and tells you to rerun `just setup`. By default the helper uses `~/Library/Caches/goose2-dev` on macOS, or `$XDG_CACHE_HOME/goose2-dev` / `~/.cache/goose2-dev` elsewhere. It prefers `origin/baxen/goose2` and falls back to `origin/main` when that branch does not exist yet.
-
-Override the shared cache root or branch with `GOOSE_DEV_ROOT=/path/to/cache` and `GOOSE_DEV_BRANCH=my/integration-branch`. You can also override the checkout path directly with `GOOSE_DEV_REPO=/path/to/goose`, or the clone source with `GOOSE_DEV_CLONE_URL=...`.
+`just setup` installs UI workspace dependencies, builds the SDK package, and builds the local debug `goose` CLI binary. `just dev` exports `GOOSE_BIN` to that local binary and loads `src-tauri/tauri.dev.conf.json`, which clears the production `externalBin` requirement during development.
 
 Run `just` to list available commands, or see [justfile](./justfile) for the full recipe definitions.