HTTP transport to the Kdenlive scripting fork — the JVM boundary.

Strata:
  Pure      routes/request        (kdenlive.routes, portable)
  Port      IKdenlive             — call a catalog route, get data back
  Boundary  HttpKdenlive          — java.net.http, JSON wire
  Seam      *kdenlive*            — read at call time; rebind in tests

The wire encoding is JSON; requests carry the route's :body as the JSON
object and responses are decoded to Clojure data with keyword keys.

The :document transport: IKdenlive over a project file, with no Kdenlive.

`http-kdenlive` sends a catalog route to the scripting fork. This adapter
answers the same route ids against a timeline kept on disk as EDN
(hive-kdenlive.mlt.timeline), and after every edit writes the MLT document
melt renders beside it:

  edit.hkd.edn   the timeline, the source of truth
  edit.mlt       its MLT rendering, rewritten on every change

:render/start renders that document with melt. Media is probed with
`melt <file> -consumer xml`, the same engine the render uses, so a length
the timeline trusts is a length the render will agree with.

Routes with no meaning off a running application (playback, render jobs)
answer :document/unsupported-route, naming the routes that are supported.

Route catalog for the Kdenlive scripting fork's HTTP transport — pure data.

The catalog is the single source: each route names its id, HTTP method,
path template, and required/optional params. The client boundary walks
this data; adding an endpoint is a catalog entry, never new client code.

Portable: core + string only.