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

internal/testrun/driver.go

@@ -0,0 +1,72 @@
+package testrun
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"strconv"
+
+	"github.com/priyanshujain/sanderling/internal/android"
+	"github.com/priyanshujain/sanderling/internal/driver"
+	"github.com/priyanshujain/sanderling/internal/driver/chrome"
+	driverSidecar "github.com/priyanshujain/sanderling/internal/driver/sidecar"
+	"github.com/priyanshujain/sanderling/internal/sidecar"
+)
+
+// buildDriver creates the appropriate DeviceDriver for the platform and returns
+// a cleanup function. For web, ChromeDriver is used directly; for android/ios
+// the JVM sidecar is extracted, spawned, and dialed.
+func buildDriver(ctx context.Context, options Options, stdout io.Writer) (driver.DeviceDriver, func(), error) {
+	if options.Platform == "web" {
+		d := chrome.New()
+		return d, func() { _ = d.Terminate(context.Background()) }, nil
+	}
+
+	sidecarDirectory := os.TempDir() + "/sanderling-sidecar"
+	jarPath, err := sidecar.Extract(sidecarDirectory)
+	if err != nil {
+		return nil, nil, fmt.Errorf("extract sidecar: %w", err)
+	}
+	fmt.Fprintf(stdout, "sidecar JAR: %s (size=%d)\n", jarPath, sidecar.EmbeddedSize())
+
+	sidecarPort, err := pickFreePort()
+	if err != nil {
+		return nil, nil, err
+	}
+	sidecarCommand := exec.CommandContext(ctx, "java", "-jar", jarPath,
+		"--port", strconv.Itoa(sidecarPort),
+		"--platform", options.Platform,
+	)
+	sidecarCommand.Stdout = stdout
+	sidecarCommand.Stderr = stdout
+	sidecarCommand.Env = android.EnvWithAndroidPlatformTools(os.Environ())
+	if err := sidecarCommand.Start(); err != nil {
+		return nil, nil, fmt.Errorf("spawn sidecar: %w", err)
+	}
+	fmt.Fprintf(stdout, "sidecar pid=%d listening on 127.0.0.1:%d\n", sidecarCommand.Process.Pid, sidecarPort)
+
+	driverClient, err := driverSidecar.Dial(fmt.Sprintf("127.0.0.1:%d", sidecarPort))
+	if err != nil {
+		_ = sidecarCommand.Process.Kill()
+		return nil, nil, fmt.Errorf("dial sidecar: %w", err)
+	}
+	healthCtx, healthCancel := context.WithTimeout(ctx, sidecarStartupTimeout)
+	if err := driverClient.WaitForHealth(healthCtx, 250e6); err != nil {
+		healthCancel()
+		_ = sidecarCommand.Process.Kill()
+		_ = driverClient.Close()
+		return nil, nil, fmt.Errorf("sidecar health check: %w", err)
+	}
+	healthCancel()
+	fmt.Fprintln(stdout, "sidecar is healthy")
+
+	cleanup := func() {
+		_ = driverClient.Close()
+		if sidecarCommand.Process != nil {
+			_ = sidecarCommand.Process.Kill()
+		}
+	}
+	return driverClient, cleanup, nil
+}