Spend guardrails

Set a daily budget in Settings and Solenta tracks today's spend across all providers. Once the cap is reached, new runs are blocked until tomorrow. Token usage and cost are visible per thread in the composer footer, so there are no surprise bills from a runaway loop.

A second cap, per-orchestration budget, bounds what one fan-out can spend across all the workers it spawns: the case where a runaway loop gets expensive fastest. Leave it empty for no ceiling; when a wake-up is held back by it, the thread says so instead of stalling silently.

Max concurrent runs in Settings, Spending caps how many runs go at once across all projects (default 4; empty for no cap). A start beyond the cap is queued on its thread with a Queued #N note and starts, oldest first, as a slot frees up.