feat(tests): migrate to global "setups" system for test configuration

This PR refactors the integration test system from suite-specific "contexts" to global "setups".
This provides better separation of concerns: **suites = what to test, setups = how to configure.**

Key changes:
- New `tests/integration/setups.py` with global, reusable configurations (ollama, vllm, gpt, claude)
- Simplified `tests/integration/suites.py` to only define test collection roots + default setup references
- Updated CLI from `--context` to `--setup` parameter that works with any suite
- Modified `scripts/integration-tests.sh` to use `--test-setup` instead of `--test-context`
- Updated documentation to reflect the new global setup system

Benefits:
- Setups can be reused across multiple suites (e.g., use "gpt" with any suite)
- Clear separation between test selection (suites) and configuration (setups)
- Easier to add new configurations without modifying existing suites
- Centralized configuration management

Usage examples:
- `pytest tests/integration --suite=responses --setup=gpt`
- `pytest tests/integration --suite=vision --setup=ollama`
- `pytest tests/integration --suite=base --setup=vllm`

.github/actions/setup-test-environment/action.yml

@@ -8,11 +8,11 @@ inputs:
   client-version:
     description: 'Client version (latest or published)'
     required: true
-  provider:
-    description: 'Provider to setup (ollama or vllm)'
-    required: true
+  setup:
+    description: 'Setup to configure (ollama, vllm, gpt, etc.)'
+    required: false
     default: 'ollama'
-  test-suite:
+  suite:
     description: 'Test suite to use: base, responses, vision, etc.'
     required: false
     default: ''
@@ -30,13 +30,13 @@ runs:
         client-version: ${{ inputs.client-version }}
 
     - name: Setup ollama
-      if: ${{ inputs.provider == 'ollama' && inputs.inference-mode == 'record' }}
+      if: ${{ (inputs.setup == 'ollama' || inputs.setup == 'ollama-vision') && inputs.inference-mode == 'record' }}
       uses: ./.github/actions/setup-ollama
       with:
-        test-suite: ${{ inputs.test-suite }}
+        suite: ${{ inputs.suite }}
 
     - name: Setup vllm
-      if: ${{ inputs.provider == 'vllm' && inputs.inference-mode == 'record' }}
+      if: ${{ inputs.setup == 'vllm' && inputs.inference-mode == 'record' }}
       uses: ./.github/actions/setup-vllm
 
     - name: Build Llama Stack