feat(tests): migrate to global "setups" system for test configuration (#3390)

This PR refactors the integration test system to use global "setups"
which provides better separation of concerns:

**suites = what to test, setups = how to configure.**

NOTE: if you naming suggestions, please provide feedback

Changes:
- New `tests/integration/setups.py` with global, reusable configurations
(ollama, vllm, gpt, claude)
- Modified `scripts/integration-tests.sh` options to match with the
underlying pytest options
    - Updated documentation to reflect the new global setup system

The main benefit is that setups can be reused across multiple suites
(e.g., use "gpt" with any suite) even though sometimes they could
specifically tailored for a suite (vision <> ollama-vision). It is now
easier to add new configurations without modifying existing suites.

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

.github/workflows/record-integration-tests.yml

@@ -10,19 +10,19 @@ run-name: Run the integration test suite from tests/integration
 on:
   workflow_dispatch:
     inputs:
-      test-provider:
-        description: 'Test against a specific provider'
+      test-setup:
+        description: 'Test against a specific setup'
         type: string
         default: 'ollama'
-      test-suite:
+      suite:
         description: 'Test suite to use: base, responses, vision, etc.'
         type: string
         default: ''
-      test-subdirs:
-        description: 'Comma-separated list of test subdirectories to run; overrides test-suite'
+      subdirs:
+        description: 'Comma-separated list of test subdirectories to run; overrides suite'
         type: string
         default: ''
-      test-pattern:
+      pattern:
         description: 'Regex pattern to pass to pytest -k'
         type: string
         default: ''
@@ -39,10 +39,10 @@ jobs:
         run: |
           echo "::group::Workflow Inputs"
           echo "branch: ${{ github.ref_name }}"
-          echo "test-provider: ${{ inputs.test-provider }}"
-          echo "test-suite: ${{ inputs.test-suite }}"
-          echo "test-subdirs: ${{ inputs.test-subdirs }}"
-          echo "test-pattern: ${{ inputs.test-pattern }}"
+          echo "test-setup: ${{ inputs.test-setup }}"
+          echo "suite: ${{ inputs.suite }}"
+          echo "subdirs: ${{ inputs.subdirs }}"
+          echo "pattern: ${{ inputs.pattern }}"
           echo "::endgroup::"
 
       - name: Checkout repository
@@ -55,16 +55,16 @@ jobs:
         with:
           python-version: "3.12"  # Use single Python version for recording
           client-version: "latest"
-          provider: ${{ inputs.test-provider || 'ollama' }}
-          test-suite: ${{ inputs.test-suite }}
+          setup: ${{ inputs.test-setup || 'ollama' }}
+          suite: ${{ inputs.suite }}
           inference-mode: 'record'
 
       - name: Run and record tests
         uses: ./.github/actions/run-and-record-tests
         with:
           stack-config: 'server:ci-tests'  # recording must be done with server since more tests are run
-          provider: ${{ inputs.test-provider || 'ollama' }}
+          setup: ${{ inputs.test-setup || 'ollama' }}
           inference-mode: 'record'
-          test-suite: ${{ inputs.test-suite }}
-          test-subdirs: ${{ inputs.test-subdirs }}
-          test-pattern: ${{ inputs.test-pattern }}
+          suite: ${{ inputs.suite }}
+          subdirs: ${{ inputs.subdirs }}
+          pattern: ${{ inputs.pattern }}