Initial commit: last30days skill

Research topics across Reddit + X from the last 30 days using
OpenAI and xAI APIs. Features:
- Auto model selection (GPT-5.x, Grok-3)
- Popularity-aware scoring (relevance + recency + engagement)
- Reddit thread enrichment with real metrics
- Near-duplicate detection
- Multiple emit modes (compact, json, context, path)
- 24h caching with --refresh bypass
- NUX for API key setup
- 87 passing unit tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

fixtures/models_openai_sample.json

@@ -0,0 +1,41 @@
+{
+  "object": "list",
+  "data": [
+    {
+      "id": "gpt-5.2",
+      "object": "model",
+      "created": 1704067200,
+      "owned_by": "openai"
+    },
+    {
+      "id": "gpt-5.1",
+      "object": "model",
+      "created": 1701388800,
+      "owned_by": "openai"
+    },
+    {
+      "id": "gpt-5",
+      "object": "model",
+      "created": 1698710400,
+      "owned_by": "openai"
+    },
+    {
+      "id": "gpt-5-mini",
+      "object": "model",
+      "created": 1704067200,
+      "owned_by": "openai"
+    },
+    {
+      "id": "gpt-4o",
+      "object": "model",
+      "created": 1683158400,
+      "owned_by": "openai"
+    },
+    {
+      "id": "gpt-4-turbo",
+      "object": "model",
+      "created": 1680566400,
+      "owned_by": "openai"
+    }
+  ]
+}