Add US-3 region to credential setup documentation

The auth module already accepts any base_url, so US-3 works mechanically;
this documents it so users know the host. Adds the US-3 base URL
(api.us-3.crowdstrike.com) to the setup skill's multi-cloud profile
examples and the README region notes, alongside a US-GOV-1 example that
was also missing. Base URLs match the FalconPy BaseURL enum.

Author: mraible

README.md

@@ -62,6 +62,7 @@ For CI or a one-off override, set environment variables instead:
 export FALCON_CLIENT_ID=your_client_id_here
 export FALCON_CLIENT_SECRET=your_client_secret_here
 # export FALCON_BASE_URL=https://api.crowdstrike.com  # US-1 (default)
+# US-2: https://api.us-2.crowdstrike.com · US-3: https://api.us-3.crowdstrike.com · EU-1: https://api.eu-1.crowdstrike.com · US-GOV-1: https://api.laggar.gcw.crowdstrike.com
 ```
 
 Credentials come from environment variables (checked first) or the TOML profile, and are never hardcoded. Verify your setup:
@@ -269,7 +270,7 @@ python common/scripts/auth.py          # Verify credentials resolve and a token
 /crowdstrike-falcon-fusion:setup        # Re-run interactive credential setup (Claude Code)
 ```
 
-Confirm `FALCON_CLIENT_ID` and `FALCON_CLIENT_SECRET` are set in your environment or TOML profile, and that `FALCON_BASE_URL` points at the correct cloud (US-1 is the default; set it for US-2, EU-1, or US-GOV).
+Confirm `FALCON_CLIENT_ID` and `FALCON_CLIENT_SECRET` are set in your environment or TOML profile, and that `FALCON_BASE_URL` points at the correct cloud (US-1 is the default; set it for US-2, US-3, EU-1, or US-GOV).
 
 ### Stale action cache
 

skills/setup/SKILL.md

@@ -93,10 +93,20 @@ base_url = "https://api.us-2.crowdstrike.com"
 # client_secret = ""
 # base_url = "https://api.crowdstrike.com"
 #
+# [us-3]
+# client_id = ""
+# client_secret = ""
+# base_url = "https://api.us-3.crowdstrike.com"
+#
 # [eu-1]
 # client_id = ""
 # client_secret = ""
 # base_url = "https://api.eu-1.crowdstrike.com"
+#
+# [us-gov-1]
+# client_id = ""
+# client_secret = ""
+# base_url = "https://api.laggar.gcw.crowdstrike.com"
 ```
 
 After creating the file, restrict its permissions (skip on Windows, where the user