builtin-plugins

What changes

• Stacked usage lines (bug). view.mergeRows drew every live row the stored history did not hold after the whole history. A turn's usage line is never stored, so each message sent piled every earlier turn's line together above it. A live row is now drawn after the stored row the live row before it matched. Regression cases in dotbotPanel.testSuite (4/4 pass).
• Space for the conversation. Agents are one line each, the section is about three agents tall and resizable by dragging its top edge, and their combined usage sits on its heading. The composer footer is one line: context against the window, the bar with its handle, and an info button whose hover (or press, which pins it) shows where it compacts and what the last turn and the conversation used. Nothing was removed.
• Transcript. A turn's thinking and tool calls are one rounded card. A tool call is a dot (done, running, failed, stopped), its name and what it was called on. The usage line names who paid only on the first turn and when it changes.
• Look. View.palette() lays DotBot's colours and radii over the editor's palette; JetBrains Mono (shipped with the engine) for code, tool names and figures. The editor's own controls (text field, chips, menus) keep their look.
• dotbotPanelPreview.module. Draws this world's panel over a fake plugin with example data as a 'DotBot preview' tab, so a panel change can be seen before it is published: luau --lang luau 'require("/source/dotbotPanelPreview.module").open()'.
• READMEs for the plugin (was the unfilled template), the panel, view and transcript.
• .world_settings (separate commit): this world had none, and the one an engine seeds names scenes.main, which this world does not hold, so every push was refused. startup_scene is cleared.

Not done here

• The engine's dotbot_panel suite tests the built-in library's pinned copy, so it has not run against these changes. Some of its cases may read the old layout (the 40% agents share, the two usage lines) and will need to follow when the pin moves to this.
• Publishing plugin.wasm and moving the engine's pin are untouched.