feat(dev): an Android failure looks exactly like a success

The APK installs and launches. It also dies six milliseconds later, and
finding that out cost a cycle for three reasons that have nothing to do
with the bug itself:

**Go's stdout does not reach logcat.** An Android app's fd 1 and 2 go
to /dev/null, so every slog line -- including the one naming the error
the app is about to exit on -- is discarded. `setprop
log.redirect-stdio true` does not help: that redirects the Java
runtime's System.out, and our code is a c-shared native library.

**os.Exit leaves no evidence.** No panic, no AndroidRuntime stack,
nothing in /data/tombstones, nothing in `logcat -b crash` or dropbox.
All three places anyone would look are empty, and the one signal that
is present -- "Zygote: exited due to signal 9" -- reads as "the system
killed it" and sends you after the low-memory killer.

**ActivityManager restarts it faster than you can observe.** pidof
always answers and `am start` always reports Status: ok, so a
crash-looping app looks alive. "Did it start" is the wrong question;
`make android-smoke` asks whether it is the *same pid* N seconds later,
and prints the filtered logcat plus how to read it when it is not.

The tell, once known: "I/WailsBridge: Wails bridge initialized"
followed immediately by a new pid doing the same thing.

scripts/android-emulator.sh follows dev-headless.sh's shape --
background start, saved-PID stop, filtered log tail, never pkill -f.
Two scaffold tasks are deliberately not wrapped: `android:logs` greps
logcat for (Wails|yellowjacket), which catches the WailsBridge tag but
misses the app's own process tag (app.yellowjacket is lowercase) and
misses ActivityManager's "has died" line, which is the one that says it
crashed; and `ensure-emulator` boots whatever `-list-avds | tail -1`
returns, with no pidfile and no boot wait, so it cannot be sequenced.

One environment note that is not obvious on Arch: Gradle needs a
platform and /opt/android-sdk has none, so ANDROID_SDK defaults to
~/Android/Sdk while ANDROID_NDK points at /opt/android-ndk. Two SDKs,
one for each half of the build.

Makefile

@@ -38,6 +38,46 @@ dev-stop: ## Stop the headless app (SIGTERM, so shutdown hooks run)
 dev-logs: ## Tail the headless app log
 	@tail -f .dev/app.log
 
+# ---------------------------------------------------------------- #
+# The Android tier.  See .pi/skills/yellowjacket-dev/references/     #
+# android-tier.md for which of these to reach for and why a failure  #
+# here looks like nothing at all.                                    #
+# ---------------------------------------------------------------- #
+
+# The NDK is pinned: r26d is what the pipeline is built and checked
+# against, and newer NDKs have broken Wails' Android build before.
+# ANDROID_HOME must carry a *platform*, which Arch's /opt/android-sdk
+# does not — hence the separate default.
+ANDROID_SDK ?= $(HOME)/Android/Sdk
+ANDROID_NDK ?= /opt/android-ndk
+ANDROID_ENV := ANDROID_HOME=$(ANDROID_SDK) ANDROID_SDK_ROOT=$(ANDROID_SDK) ANDROID_NDK_HOME=$(ANDROID_NDK)
+
+android: build-frontend ## Build the fat APK (arm64 + x86_64) into bin/
+	@$(ANDROID_ENV) PATH="$(TOOLBIN):$$PATH" go tool wails3 task android:package:fat
+
+android-setup: ## Install the SDK pieces and create the AVD (once, ~3.5GB)
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh setup
+
+android-emulator: ## Boot the emulator headless in the background and wait for it
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh start
+
+android-emulator-stop: ## Shut the emulator down (console kill, then saved PID)
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh stop
+
+android-install: ## Install bin/yellowjacket.apk onto the running emulator
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh install
+
+android-launch: ## Force-stop, clear logcat, and start the app
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh launch
+
+android-logs: ## Tail logcat, filtered to the app's own tags
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh logs
+
+# "Did it start" is the wrong question — a crash-looping app starts
+# several times a second.  This asserts the *same pid* is still there.
+android-smoke: ## Launch and assert the app is still alive (SECONDS=<n>)
+	@$(ANDROID_ENV) ./scripts/android-emulator.sh smoke $(if $(SECONDS),$(SECONDS),10)
+
 # Seeds are produced by *running the app* — driving the real AddLibrary
 # binding and waiting for the real scan — never by hand-writing a
 # config.toml and DB rows.  A hand-built seed is a second description