slice 1.0.5: system prompt for the todo-app happy path

[sausi-7]

Phase 1.0 demo slice · Difficulty: D1 (good first issue)

Scope

packages/agent-core/prompts/system_demo.md. Tight prompt that, given the user prompt "Build me a todo app with localStorage" and access to a pre-seeded Angular starter, produces a working app.

Acceptance criteria

• Markdown file with: project layout assumptions, tools available, Angular 19 conventions (standalone, Signals, new control flow).
• Manually verified: prompt + Anthropic + the two tools produces a runnable todo app on at least 3 of 5 attempts.
• Failure modes documented in the file's footer.