Changelog

Unreleased

Make dependency selection independent of whichever repository first loaded the shared DependencySources module. Source-workspace builds pass the Execution Plane repository root explicitly; published-package builds use the call-site Hex requirements without reading a consumer's workspace registry.

Make the published package loadable by any consumer. 0.2.1 and 0.2.2 required build_support/dependency_sources.exs from a path outside the tarball, so mix compile in a consuming project died while Mix loaded this dependency's project. Both are retired.
mix.exs now detects whether it is running inside the workspace checkout. In the workspace it resolves siblings through the dependency-source registry as before; anywhere else it declares plain Hex requirements and never touches build_support.

Make the published package self-describing. mix.exs resolved its dependencies through the workspace dependency-source registry, reading a config file two directories above itself — a path that exists in this checkout and not inside a published tarball, which does not ship build_support/. Any consumer resolving execution_plane from Hex failed while Mix loaded the dependency's project. 0.2.1 shipped with this defect.
Dependency source resolution now treats an absent registry as the ordinary state of a published package rather than a missing file, and falls back to the hex: requirement stated at the call site. Local development still resolves siblings by path, unchanged.

Remove two unreachable normalize_atomish/1 heads in ExecutionPlane.Placements.Capabilities. The function is only ever reached from the is_binary branch of fetch_member/4, so its atom and catch-all clauses were dead code the compiler had already proved unreachable. No behavioural change.

Publish execution_plane as the common core-only substrate; JSON-RPC and process runtime ownership now lives exclusively in their component packages.
Add the admitted interactive runtime lifecycle contracts, bounded runtime errors and status/events, attach and input envelopes, and their boundary codecs.
Replace the former execute/stream runtime-client callbacks with the start/subscribe/input/status/cancel lifecycle.

Initial release.