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>

.gitignore

@@ -0,0 +1,39 @@
+# Repo-root ignores. Module-level rules live next to their module
+# (see echolot-prober/.gitignore for the Android-specific set).
+
+# OS noise
+.DS_Store
+Thumbs.db
+desktop.ini
+
+# IDEs
+.idea/
+*.iml
+*.swp
+*~
+
+# Machine-specific build config — never commit (contains local SDK paths)
+local.properties
+
+# Gradle / Android build output
+.gradle/
+build/
+*.apk
+*.aab
+
+# Signing material
+*.keystore
+*.jks
+keystore.properties
+
+# Go server (future sibling module)
+/server/bin/
+*.test
+
+# Secrets / environment
+.env
+.env.*
+!.env.example
+
+# Claude Code: settings.json is shared, per-machine overrides are not
+.claude/settings.local.json