refactor: code organization cleanup (#35)

* chore: fix gitignore + decisions doc after web->inspect-ui rename

Update web/ references to inspect-ui/ in .gitignore and Makefile. Add
decisions.md tracking architectural decisions from code-org discussion.

* refactor: rename pkg/spec-api to pkg/spec

Aligns the directory name with the npm package name @sanderling/spec.
Updates Makefile, package.json directory field, and resolveSpecAPIPath.

* refactor(verifier): split bindings.go into types.go + bindings.go

Move shared public types (Action, ActionKind, LogEntry, Exception) to
types.go. bindings.go retains internal JS runtime wiring only.

* refactor(inspect): split runs.go into runs.go, runs_cache.go, runs_decode.go

runs.go: types (RunSummary, StepSummary, RunDetail, Run) and Scan.
runs_cache.go: Cache type, Open/Step/Detail methods, parseRun, scanSteps.
runs_decode.go: readMeta, tallyTrace, decodeStepSummary, validRunID.

* refactor: move android_env.go to internal/android/

Extracts Android device/AVD/adb logic into internal/android package.
Exports EnsureDevice, AdbReverse, AdbReverseRemove, EnvWithAndroidPlatformTools, AdbBinary.
Moves tests to internal/android/android_test.go. cmd/sanderling becomes a thin caller.

* refactor: extract test pipeline to internal/testrun/

runTestPipeline logic moves to testrun.Execute. buildDriver, resolveSpecAPIPath,
pickFreePort, and the progress logger move to internal/testrun/. cmd/sanderling/test_run.go
becomes a thin adapter. Tests follow their code.

* ci: update workflow paths after pkg/spec-api -> pkg/spec rename

pkg/spec/README.md

@@ -0,0 +1,39 @@
+# @sanderling/spec
+
+TypeScript spec API for [sanderling](https://github.com/priyanshujain/sanderling), a property-based UI fuzzer for mobile apps.
+
+Spec authors write specs in TypeScript that describe what an app should *always* do (safety invariants), generate weighted actions to exercise the app, and extract structured state from the accessibility tree. The `sanderling` CLI picks up the spec and drives the app under test.
+
+## Install
+
+```sh
+npm install --save-dev @sanderling/spec
+```
+
+## Usage
+
+```ts
+import { extract, always, actions, Tap, weighted } from "@sanderling/spec";
+
+export const spec = {
+  extract: extract((tree) => ({
+    onHomeScreen: tree.some((n) => n.text === "Home"),
+  })),
+
+  always: always(({ state }) => state.onHomeScreen || !state.startedOnHome),
+
+  actions: actions(({ tree }) =>
+    weighted([
+      [1, Tap(tree.first((n) => n.text === "Checkout"))],
+    ]),
+  ),
+};
+```
+
+## Version compatibility
+
+`@sanderling/spec` is released in lockstep with the sanderling CLI. Pin the same major/minor version as your installed `sanderling` binary.
+
+## License
+
+Apache-2.0