feat(registry): commands, watches, samples, the timeline and conditions

The app side of Crafter.Debug, minus the session:

- Command(name, description, handler): the handler takes nothing or
  one argument struct and returns void, a value, Result<T> or
  Async<T>. Arguments are decoded before it runs, so a mistyped call
  is answered with every mistake and never reaches it; a throwing
  handler becomes an Exception error instead of unwinding into the
  frame loop. This replaces 3DForts' three-file pattern per verb.
- Watch(path, variable | getter [, setter]) with bounds, help and
  read-only, and Sample(path, value) from any thread with a
  frame-stamped history. Paths resolve into values ("bodies[1].pos.y")
  and set the same way, writing a member writes the whole value back.
  Unknown paths and commands get a suggestion.
- Group: registrations under a prefix that end with their owner. Not
  movable, so neither is its owner: its watches refer to the owner's
  members, and a move would leave them pointing at the old object.
- Log, LogWarn, LogError, Check and Emit on one frame-stamped
  timeline, with source locations captured without macros. A check
  failing every frame is counted every time but stored sparsely, and
  the session's listener hears every failure.
- Condition: what `wait` and `pause --when` evaluate each frame. A
  condition that cannot be decided reports why instead of being false,
  which would make a wait hang.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

interfaces/Crafter.Debug.cppm

@@ -1,11 +1,15 @@
 // SPDX-License-Identifier: LGPL-3.0-only
 // SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
 
-// Runtime debugging for AI agents: what an app imports. The session, the
-// registry of commands and watches, the timeline and pause control follow in
-// later phases; for now this re-exports the shared core.
+// Runtime debugging for AI agents: what an app imports. Commands, watches
+// and samples (:Registry), the timeline with Log, Check and Emit
+// (:Timeline), and the conditions waits and pauses use (:Condition), over
+// the core shared with the client. The session follows in a later phase.
 export module Crafter.Debug;
 export import Crafter.Debug.Core;
+export import :Registry;
+export import :Timeline;
+export import :Condition;
 import std;
 
 export namespace Crafter::Debug {