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/src/index.ts

@@ -0,0 +1,40 @@
+export type {
+  AccessibilityElement,
+  AccessibilityTree,
+  Action,
+  ActionGenerator,
+  EventuallyFormula,
+  ExceptionRecord,
+  Extracted,
+  Formula,
+  InputTextAction,
+  Key,
+  LogEntry,
+  Point,
+  PressKeyAction,
+  Sampler,
+  Snapshots,
+  State,
+  SwipeAction,
+  TapAction,
+  SanderlingRuntime,
+  WaitAction,
+  WeightedEntry,
+} from "./types.ts";
+
+export { extract } from "./extract.ts";
+export { always, eventually, next, now } from "./ltl.ts";
+export {
+  InputText,
+  PressKey,
+  Swipe,
+  Tap,
+  Wait,
+  actions,
+  from,
+  pressKey,
+  swipes,
+  taps,
+  waitOnce,
+  weighted,
+} from "./actions.ts";