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

Makefile

@@ -25,7 +25,7 @@ WEB_DIST := inspect-ui/dist
 bootstrap:
 	$(GO) mod download
 	$(BUF) generate
-	cd pkg/spec-api && npm install --silent
+	cd pkg/spec && npm install --silent
 
 proto:
 	$(BUF) lint
@@ -82,7 +82,7 @@ test-kotlin:
 	ANDROID_HOME=$(ANDROID_HOME) $(GRADLE) :sidecar:test :sdk-android:testDebugUnitTest
 
 test-spec-api:
-	cd pkg/spec-api && npm test --silent
+	cd pkg/spec && npm test --silent
 
 docs: $(DOCS_OUT) build/site/_assets $(DIAGRAM_OUT)
 	@echo "built $(words $(DOCS_OUT)) pages, $(words $(DIAGRAM_OUT)) diagrams to build/site"
@@ -118,4 +118,4 @@ release-android-local:
 	  ANDROID_HOME=$(ANDROID_HOME) $(GRADLE) :sdk-android:publishToMavenLocal -Psanderling.version=0.0.0-local
 
 release-npm-dry:
-	cd pkg/spec-api && npm ci && npm run build && npm pack --dry-run
+	cd pkg/spec && npm ci && npm run build && npm pack --dry-run