Add Vertex AI routing support (#753)

* add Vertex AI routing support

* include Vertex smokes in action CI

.github/workflows/test.yml

@@ -38,6 +38,8 @@ jobs:
             skill-invoke-opencode,
             smoke,
             token-exfil,
+            vertex-claude,
+            vertex-opencode,
           ]
         exclude:
           - agent: claude
@@ -61,6 +63,10 @@ jobs:
       AWS_BEARER_TOKEN_BEDROCK: ${{ secrets.AWS_BEARER_TOKEN_BEDROCK }}
       AWS_REGION: us-east-1
       BEDROCK_MODEL_ID: us.anthropic.claude-opus-4-6-v1
+      VERTEX_SERVICE_ACCOUNT_JSON: ${{ secrets.VERTEX_SERVICE_ACCOUNT_JSON }}
+      GOOGLE_CLOUD_PROJECT: pullfrog
+      VERTEX_LOCATION: global
+      VERTEX_MODEL_ID: gemini-2.5-flash
       PULLFROG_MODEL: ${{ vars.PULLFROG_MODEL }}
       # CI smoke-testing shortcut only — production stores this in Pullfrog's
       # per-org secret store (Postgres), set via `pullfrog auth codex`. GH