[u7-u7]

Problem

A fresh checkout cannot typecheck or test the extension. apps/extension/tsconfig.json (tracked) extends ./.wxt/tsconfig.json, which is gitignored and only produced by wxt prepare. Nothing generates it during install, so the commands README lists for checks fail immediately:

$ rm -rf apps/extension/.wxt          # same state as a fresh checkout
$ pnpm --filter @browser-skill/extension compile
> tsc --noEmit
error TS2318: Cannot find global type 'AsyncIterableIterator'.
error TS2318: Cannot find global type 'IterableIterator'.
# exit 2

$ pnpm --filter @browser-skill/extension test
 [TSCONFIG_ERROR] Failed to load tsconfig for 'src/vitest-setup.ts': Tsconfig not found
 Test Files  212 failed (212)
# exit 1

Root cause

The generated .wxt/ tree is a build input that install never produces:

• wxt build and wxt dev generate it as a side effect, so the order "install, build, test" happens to work;
• .github/workflows/ci.yml therefore needs a dedicated workaround step (pnpm --filter @browser-skill/extension exec wxt prepare) before compile/ext:test;
• anyone who runs the documented check commands before building (new contributor, reviewer pulling a PR branch, git clean -xdf in the extension) gets 212 failing test files and a broken tsc, which looks like a broken branch rather than missing generated types.

Fix

Run the generator from the extension package's postinstall script:

     "test": "vitest run",
-    "test:watch": "vitest"
+    "test:watch": "vitest",
+    "postinstall": "wxt prepare"

This is the layout WXT projects use, and it makes pnpm install leave the working tree in a state where the documented checks work. No dependency, lockfile, CI, or product code is touched; CI's explicit prepare step stays valid (now redundant) and I left it alone.

Reproduction and verification

$ rm -rf apps/extension/.wxt                       # simulate a fresh checkout
$ pnpm install --frozen-lockfile
apps/extension postinstall$ wxt prepare
apps/extension postinstall: WXT 0.20.26
apps/extension postinstall: ℹ Generating types...
apps/extension postinstall: ✔ Finished in 888 ms
apps/extension postinstall: Done
Done in 4s using pnpm v10.17.0
# exit 0

$ ls apps/extension/.wxt
tsconfig.json
types
wxt.d.ts

$ pnpm --filter @browser-skill/extension compile
> tsc --noEmit
# exit 0

$ pnpm ext:test
 Test Files  1 failed | 177 passed | 34 skipped (212)
      Tests  1 failed | 2972 passed | 263 skipped (3236)
# exit 1   (see below)

The 212 type-less failures are gone: 2972 tests now run. The single remaining failure is not caused by this change and is not fixed here: src/long-screenshot/png.test.ts > encodes 120,000 exact scanlines across tile and compression boundaries exceeded vitest's default 5000 ms timeout (6065ms) under full-suite parallelism. In three full-suite runs I got 2972 passing tests each time and exactly one default-timeout failure, on a different heavy test each run (png.test.ts twice; once human-loop.test.ts > bounds dangerous URL regex checks in a child process, whose own spawnSync budget is 10 s but which vitest kills at 5 s). Both pass in isolation (png.test.ts: 12/12 in 2.8 s). I kept this patch single-purpose instead of also raising testTimeout — happy to send that as a separate PR if you want it.

Impact and risk

• Affects local development install only: one extra wxt prepare (~1 s) per pnpm install for the workspace package.
• No change to the extension runtime, the CLI, the protocol, or the lockfile (pnpm install --frozen-lockfile still passes).
• If you would rather keep install script-free, the alternative is a README line in "For Developers" telling contributors to run wxt prepare (or pnpm ext:build) before pnpm ext:test; that is strictly a documentation fix and leaves the trap in place for reviewers and git clean -xdf.

AI assistance: this patch was prepared with AI assistance; I reproduced the failure and verified the fix with the commands above.