Don't build on Windows at all, add hello_world doc

Author: russellhancox

extensions/gcs/description.yml

@@ -6,11 +6,25 @@ extension:
   language: C++
   build: cmake
   license: MIT
-  excluded_platforms: "wasm_mvp;wasm_eh;wasm_threads;windows_amd64_mingw"
+  excluded_platforms: "wasm_mvp;wasm_eh;wasm_threads;windows_amd64_mingw;windows_amd64"
   maintainers:
     - northpolesec
 
 repo:
   github: northpolesec/duckdb-gcs
   ref: b0b3bd3e896417308800a04116cf60a129de7e0c
 
+docs:
+  hello_world: |
+    -- Add auth credentials using Application Default Creds
+    D CREATE SECRET secret (TYPE gcp, PROVIDER credential_chain);
+
+    -- Read a file from GCS
+    D SELECT * FROM read_text('gcss://rah-public-gcs-testing/quack.txt');
+    ┌─────────────────────────────────────────┬─────────┬───────┬──────────────────────────┐
+    │                filename                 │ content │ size  │      last_modified       │
+    │                 varchar                 │ varchar │ int64 │ timestamp with time zone │
+    ├─────────────────────────────────────────┼─────────┼───────┼──────────────────────────┤
+    │ gcss://rah-public-gcs-testing/quack.txt │ 🦆      │   4   │ 2025-09-23 16:20:03-04   │
+    └─────────────────────────────────────────┴─────────┴───────┴──────────────────────────┘
+