Dashboard redesign — editorial growth ledger

Two user-visible changes:

• New dashboard theme — the app moves to an editorial, ledger-style look: calmer surfaces, tighter tables, clearer chart styling (with keyboard focus rings and tooltip fixes along the way).
• Worker environment fixed — the Compose worker now loads the app's .env; previously the worker ran without the provider configuration and DEMO_MODE, so GEO engines failed with a confusing "provider not configured" error.

Under the hood this round also shipped a series of data-correctness and robustness fixes from the ongoing review cycle.