Deepgram: STT concurrency cut, model lineup restructured, promo streaming rates

Speech-to-Text model lineup restructured: "Flux" split into separate "Flux English" and new "Flux Multilingual" line items (Multilingual priced at $0.0078/min Pay-As-You-Go, $0.0068/min Growth); Nova-1 & 2, Enhanced, and Base models removed from the main public pricing table (a new FAQ entry "Are older models (Nova-2, Enhanced, Base) still available?" was added, but their pricing is no longer shown in the comparison table); new "Limited-time promotional rates on streaming" discount reduced streaming prices for Flux English, Nova-3 Monolingual, and Nova-3 Multilingual (old prices now shown struck through next to lower promotional prices, e.g. Flux English Pay-As-You-Go $0.0077/min → $0.0065/min)

Speech-to-Text REST API concurrency limit cut in half for both the Pay As You Go plan and the Growth plan: "Up to 100 for the REST API" reduced to "Up to 50 for the REST API"