feat: free-stack combo, Deepgram transcription default, README free sections, provider hasFree badges

- Combos: add 'Free Stack ($0)' as 4th combo template (round-robin: Kiro+iFlow+Qwen+GeminiCLI)
- Media/Transcription: Deepgram (Nova 3) as default provider, show $200/$50/free badges
- providers.ts: hasFree + freeNote for NVIDIA NIM (40 RPM), Cerebras (1M tok/day), Groq (30 RPM)
- README: new early '🆓 Start Free' 5-step table before Quick Start
- README: new '🎙️ Free Transcription Combo' section (Deepgram/AssemblyAI/Groq)
- README: NVIDIA NIM model list updated (Kimi K2.5, GLM 4.7, DeepSeek V3.2)
- i18n: templateFreeStack + templateFreeStackDesc synced to 30 languages
- Bump version to 2.3.17

src/shared/constants/providers.ts

@@ -144,6 +144,8 @@ export const APIKEY_PROVIDERS = {
     color: "#F55036",
     textIcon: "GQ",
     website: "https://groq.com",
+    hasFree: true,
+    freeNote: "Free tier: 30 RPM / 14.4K RPD — no credit card",
   },
   blackbox: {
     id: "blackbox",
@@ -206,7 +208,9 @@ export const APIKEY_PROVIDERS = {
     icon: "memory",
     color: "#FF4F00",
     textIcon: "CB",
-    website: "https://www.cerebras.ai",
+    website: "https://inference.cerebras.ai",
+    hasFree: true,
+    freeNote: "Free: 1M tokens/day, 60K TPM — world's fastest inference",
   },
   cohere: {
     id: "cohere",
@@ -224,7 +228,9 @@ export const APIKEY_PROVIDERS = {
     icon: "developer_board",
     color: "#76B900",
     textIcon: "NV",
-    website: "https://developer.nvidia.com/nim",
+    website: "https://build.nvidia.com",
+    hasFree: true,
+    freeNote: "Free dev access: ~40 RPM, 70+ models (Kimi K2.5, GLM 4.7, DeepSeek V3.2...)",
   },
   nebius: {
     id: "nebius",