fix(examples): restart ball ids when the scene is cleared

World_Reset kept counting, so after one reset the ball dropped from
60 m was ball 10, not the ball 5 the plain build's output and the log
from before the reset name. The agent in the first check noticed and
worked around it. Clear now restarts ids at 1, so Reset brings back
balls 1 to 5.

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

README.md

@@ -12,7 +12,8 @@ Runtime debugging for AI agents, and for people. An app built with Crafter.Debug
 Breakpoints and memory stay with a debugger; `crafter-debug debugger` prints how to attach one.
 
 ```console
-$ crafter-build --debug-api -r &              # the app's debug build, in the background
+$ crafter-build --debug-api                   # the app's debug build, and the client with it
+$ crafter-build --debug-api -r &              # the app, in the background
 $ ./build/crafter-debug ls --wait 60s
 game  id 4f1c09a2b7e3d851  pid 3 (sandbox 48211)  up 4s  port 41207
 $ ./build/crafter-debug call Lobby_Start && ./build/crafter-debug wait --frames 30

examples/Basic/implementations/Basic.World.cpp

@@ -16,6 +16,7 @@ void Basic::World::Reset() {
 
 void Basic::World::Clear() {
     balls.clear();
+    nextId = 1;
     time = 0;
     fastest = 0;
 }

examples/Basic/interfaces/Basic.World.cppm

@@ -43,8 +43,9 @@ export namespace Basic {
         Physics physics;
         Floor floor;
 
-        // Removes every ball and drops the scene's five.
+        // Removes every ball and drops the scene's five, as balls 1 to 5.
         void Reset();
+        // Removes every ball; ids start again from 1.
         void Clear();
         // Returns the new ball's id.
         std::int32_t Spawn(float x, float y, float vy, float radius);

implementations/Crafter.Debug.Cli-Client.cpp

@@ -974,13 +974,15 @@ memory are a debugger's job; `crafter-debug debugger` prints how to attach one.
 
 ## The loop
 
-1. Build and start the app from its debug build, in the background (it does
-   not exit): `crafter-build --debug-api -r` (use the project's own flag).
-2. `./build/crafter-debug ls --wait 60s` until it is listed.
-3. `cmds` and `help <command>` to see what it offers, `get '*'` for its state.
-4. Act and observe: `call`, `set`, `pause --when`, `wait`, `step`, `trace`,
+1. Build with the debug flag, in the foreground: `crafter-build --debug-api`
+   (use the project's own flag). That build compiles this client too.
+2. Start the app in the background, since it does not exit:
+   `crafter-build --debug-api -r`.
+3. `./build/crafter-debug ls --wait 60s` until it is listed.
+4. `cmds` and `help <command>` to see what it offers, `get '*'` for its state.
+5. Act and observe: `call`, `set`, `pause --when`, `wait`, `step`, `trace`,
    `log --level warn`, `screenshot` (open the PNG it prints with Read).
-5. `quit` when done. Killing the background task may leave the app running
+6. `quit` when done. Killing the background task may leave the app running
    if crafter-build's alias lacks --die-with-parent; `ls` shows leftovers.
 
 ## Commands

tooling/AGENTS.consumer.md

@@ -4,7 +4,8 @@ This app can be driven while it runs: call its commands, read and set its state,
 
 ### Driving it
 
-- Start the debug build in the background, since it does not exit: `crafter-build <debug flag> -r`.
+- Build with the debug flag first, in the foreground: `crafter-build <debug flag>`. That build also compiles the client `./build/crafter-debug` runs. The first one takes a few minutes.
+- Then start the app in the background, since it does not exit: `crafter-build <debug flag> -r`.
 - From the project directory, use `./build/crafter-debug`:
   - `ls --wait 60s` until it is listed; `status`, `cmds`, `help <command>`, `get '*'`
   - `call <command> key=value ...`, `set <path> <value>`

tooling/interfaces/Crafter.Debug.Build.cppm

@@ -87,7 +87,7 @@ namespace Crafter::Debug {
             "# project with {0}: runs the crafter-debug client that build compiled.\n"
             "client={1}\n"
             "if [ ! -x \"$client\" ]; then\n"
-            "    echo \"crafter-debug: the client is not built yet; build with: crafter-build {0}\" >&2\n"
+            "    echo \"crafter-debug: the client is not built yet; let crafter-build {0} finish first, which builds it with the app\" >&2\n"
             "    exit 2\n"
             "fi\n",
             flag, ShellQuote(client.string()));
@@ -113,7 +113,7 @@ namespace Crafter::Debug {
         return std::format(
             "#!/bin/sh\n"
             "# Written by Crafter.Debug (Debug::Use): this project has no debug build yet.\n"
-            "echo \"crafter-debug: no debug build yet; build with: crafter-build {}\" >&2\n"
+            "echo \"crafter-debug: no debug build yet; build with: crafter-build {0}, then start the app in the background with: crafter-build {0} -r\" >&2\n"
             "exit 2\n",
             flag);
     }