Lazurio overlay: open Chat with a prompt draft from the shell (not sent) #35

Context

The Lazurio shell adds a "+ Nový modul" (new module) tile to the Apps (Launchpad) home of an Environment. Clicking it should open Chat (this fork) in the same Environment, with a prepared prompt already in the composer. The prompt tells the agent to ask what the module is for, and then to found the module with lazurio module create, following the Lazurio Module Standard.

The behaviour is drawn in the shell wireframe (HumanAndMachine-ai/prototypes-lazurio, route #/e/<env>/chat/new-module). In the wireframe the prompt sits in the composer and is not sent: the person reads it, may edit it, and sends it.

What the fork needs

Upstream T3 Code has no way to receive a prompt draft from outside. The fork needs a small overlay entry point, for example a URL parameter or a /.lazurio/ hand-off, that:

• opens a new thread (or the composer of the current one) in a chosen project;
• puts the given text into the composer without sending it;
• accepts text only from the Environment's own origin (the Lazurio shell). An arbitrary link must not be able to inject and run instructions; nothing is sent until the person sends it.

Open questions

• Which project the new thread should open in: the Organization's root task worktree, or a chooser.
• How long the text may be, and how it is passed (query string vs. a short-lived handle on the same origin).

Related: #33 (Lazurio shell slot).