Agent-readiness harness: environment bootstrap, emulator proof, evidence capture #15

Part of #14 (W0 — foundation and agent readiness). This is the first issue of the program; nearly everything else is blocked on it.

Outcome

An agent (or a human) on a fresh MacBook or devbox can go from git clone to a running, provable app without hand-holding: environment bootstrapped, both flavors building, an emulator booting, and evidence capture (screenshots/recordings) scripted. The repo's docs and tooling are good enough that autonomous agents can work here end to end.

Scope

• Reproducible toolchain bootstrap: JDK, Android SDK cmdline-tools, platform/build-tools, and AVD creation scripted (mise/Brewfile or equivalent — follow workspace conventions), local.properties handled automatically
• ./gradlew verify, :app:assembleMobileDebug, :app:assembleTvDebug green locally (fix the missing gradle.properties, plugin setup, and any AGP 9/compileSdk 37 issues on main)
• Phone AVD + TV AVD definitions with one-command create/boot/install/launch scripts
• Evidence tooling: one-command screenshot and screen-recording capture from a running emulator/device, landing in a predictable output dir for PR attachment
• putio CLI wired for live proof: documented flow for authenticating a test profile (device-code) so agents can create fixtures/verify API state; secret-free by default per workspace secrets contract
• AGENTS.md rewritten as the operating manual: setup, build, run, prove, evidence conventions, and the program's definition of done
• Devbox/cloud notes: what differs headless (emulator w/o KVM/HAXM caveats, -no-window capture)

Exit bar (settled 2026-08-08 — this is the gate, nothing more)

W0 is DONE when a fresh checkout on a second machine reaches, following only repo docs/scripts:

1. Green ./gradlew verify + both flavor builds
2. Booted phone + TV emulators via one command each
3. Working screenshot/recording capture
4. Rewritten AGENTS.md

Everything beyond (CI emulator lanes, cloud devboxes, proofs-CLI integration) lands incrementally while feature slices run — harness excellence keeps compounding but stops gating.

Acceptance criteria

• A fresh checkout on a second machine (or clean worktree) reaches green builds + booted emulator following only repo docs/scripts
• Definition of done: verification green, harness exercised, and visual proof (screenshot of both flavor shells running) attached

Emulator lifecycle acceptance

The one-command emulator flows must own what they start as well as boot it.

• Distinguish a preexisting emulator/AVD from an emulator process booted by the current invocation.
• On normal completion, failure, SIGINT, and SIGTERM, stop only the exact emulator process/serial owned by the invocation.
• Delete an AVD registration only when the command created it as explicitly ephemeral; preserve documented reusable AVDs and every preexisting emulator.
• Confirm the owned emulator is absent from the final adb device state before returning, and surface cleanup failure.
• Add focused forced-failure and interruption proof; never use broad emulator or process-name cleanup.