feat(03-07): add 8 emerging labs, writing tools, observability providers

- Reka, Aleph Alpha, Lamini (emerging LLM labs)
- Writer, Jasper, Typeface (writing tools)
- Comet ML/Opik, Weights & Biases (observability)
- Dual-located in providers/ and pkg/providers/definitions/

providers/writer.yaml

@@ -0,0 +1,17 @@
+format_version: 1
+name: writer
+display_name: Writer
+tier: 6
+last_verified: "2026-04-05"
+keywords:
+  - "writer.com"
+  - "WRITER_API_KEY"
+  - "api.writer.com"
+  - "palmyra"
+verify:
+  method: GET
+  url: https://api.writer.com/v1/models
+  headers:
+    Authorization: "Bearer {KEY}"
+  valid_status: [200]
+  invalid_status: [401, 403]