Initial commit: capability prober + design docs

Monorepo root for Echolot. Contains the no-root capability prober
(Kotlin/Compose, app.echo_lot.prober) and the four design docs that act
as the contract for the production app and the Go server.

LICENSE is deliberately absent — still undecided, see docs/build-status.md.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/build-status.md

@@ -0,0 +1,35 @@
+# Echolot — build status & next steps
+
+Last updated: 2026-07-29.
+
+## Decided
+- Name **Echolot**; domain echo-lot.app; scheme `echolot://`; namespace `app.echo_lot.*`
+  (hyphen→underscore; appIds/packages can't contain hyphens). Prober appId `app.echo_lot.prober`.
+- Stack: native **Kotlin + Jetpack Compose**, no Flutter.
+- Tiers: `app` (no root), **`shizuku` in v1** (wireless-ADB pairing), `root` future.
+- License: still undecided (GPLv3 vs Apache-2.0) — needed before repos go public.
+
+## Specs (in `docs/`, alongside this file)
+- `feature-catalog-and-feasibility.md`, `measurement-schema.md`, `probe-protocol.md`. Considered draft-complete and reviewed by the user.
+
+## Capability prober — DELIVERED (as zip, 2026-07-29)
+Full Kotlin/Compose project scaffolded: `app.echo_lot.prober`, minSdk 26 / target+compile 35,
+AGP 8.7.3, Kotlin 2.0.21, Compose BOM 2024.10, Shizuku api+provider 13.1.5, kotlinx-serialization.
+Probes implemented: `link.snapshot`, `icmp.ping4/6` (unprivileged ICMP datagram), `sockopt.matrix`
+(TTL/TOS/RECVERR/MTU_DISCOVER), `trace.errqueue_reachable`, `multinetwork.request_and_bind`,
+`local.mdns_discover`, `peer.ble_advertise`, `shizuku.command_battery` (ip neigh / ip -6 route /
+ip addr / ip monitor / dumpsys network_stack DHCP+IpClient / dumpsys wifi). JSON export via share
+intent; results carry verdict + raw evidence.
+
+Could NOT be compiled in the cloud sandbox: dl.google.com (Google Maven) and services.gradle.org
+are proxy-blocked, and no device is reachable for on-device runs. Build + iterate locally
+(Android Studio / Claude Code). Wrapper is pinned to Gradle 8.14.3.
+
+## Next steps
+1. Build locally, run on several physical devices (varied Android versions/vendors), collect the
+   JSON reports — especially the real per-device Shizuku dump formats.
+2. If `trace.errqueue_reachable` = PARTIAL, add a C-over-JNI errqueue shim (`recvmsg`+cmsg parse)
+   as a `:native` module and a real `traceroute.udp4` probe.
+3. Start the Go server skeleton (enrollment + profile + sessions + UDP echo with observation
+   blocks + canary-DNS reference records) per probe-protocol.md.
+4. Fold confirmed capabilities into the production `core-probe` / `core-shizuku` modules.