IAddon facade for hive-mcp-compatible hosts. The host loads this
namespace by name from META-INF/hive-addons/hive-elm.edn.

Command handlers. Each takes the parsed params map and returns a Result.
MCP delivers every param as a string.

IAddon record and constructor for the hive.elm addon.

The `elm` subdomain of the host's `code` tool: command table, dispatch,
and the shape the host is handed.

Boundary: reads the project's files and assembles the adapters.

IElmCompiler over a child process.

The project's watch configuration as a value. Pure.

A project needs no `hive-elm.edn`: everything has a default, and the
source directories come from the project's own elm.json.

IBuildNotifier that shouts on the host's hivemind.

The host is a runtime, not a dependency: its shout function is resolved
when a notice is delivered, never required. Outside a host the notifier
answers with an err Result and the watcher carries on.

A shout reaches the model two ways. It is piggybacked on the next tool
result of the reader it is addressed to, and sixth-sense perceives it as
`:sense/build-failed` (see hive-elm.notify.sense) and pushes it to an idle
session. Both address by `:parent-id`: without one the shout goes to
coordinator readers only.

Registers `:sense/build-failed` with sixth-sense, when it is loaded.

sixth-sense turns a shout into a sense only when a registered class
perceives it; a `:build-failed` shout matches none of the built-ins. The
registration is one map. sixth-sense belongs to hive-agent, which this
library does not depend on, so its registry is resolved softly: without
it the shout is still piggybacked, only never pushed.

Ports the watcher depends on. Adapters live in their own namespaces;
tests supply stub records.

Promote: the output of `elm make --report=json` to a Report value, and a
Report to the text an LLM reads. Pure.

Wire shapes, measured against elm 0.19.1 (fixtures in test/resources/elm):

  {"type" "compile-errors"
   "errors" [{"path" abs "name" module
              "problems" [{"title" s "region" {"start" {"line" n "column" n}}
                           "message" [chunk ...]}]}]}
  {"type" "error" "path" "elm.json" "title" s "message" [chunk ...]}

A chunk is a string, or a styled span {"string" s "color" ... "bold" ...}.
The report is written to stderr; stdout carries progress only.

Value objects of the Elm build domain.

IFileStamps over the filesystem, plus the system clock.

Pure decisions of the watcher: when a change is settled enough to compile,
and whether a report is news.

Pipeline: sample the sources, compile when a change settles, tell the
notifier when the report is news. All effects go through the ports in
`deps` ({:compiler :notifier :stamps :clock}).