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`

tests/integration/README.md

@@ -6,9 +6,7 @@ Integration tests verify complete workflows across different providers using Lla
 
 ```bash
 # Run all integration tests with existing recordings
-LLAMA_STACK_TEST_INFERENCE_MODE=replay \
-  LLAMA_STACK_TEST_RECORDING_DIR=tests/integration/recordings \
-  uv run --group test \
+uv run --group test \
   pytest -sv tests/integration/ --stack-config=starter
 ```
 
@@ -42,25 +40,35 @@ Model parameters can be influenced by the following options:
 Each of these are comma-separated lists and can be used to generate multiple parameter combinations. Note that tests will be skipped
 if no model is specified.
 
-### Suites (fast selection + sane defaults)
+### Suites and Setups
 
-- `--suite`: comma-separated list of named suites that both narrow which tests are collected and prefill common model options (unless you pass them explicitly).
+- `--suite`: single named suite that narrows which tests are collected.
 - Available suites:
-  - `responses`: collects tests under `tests/integration/responses`; this is a separate suite because it needs a strong tool-calling model.
-  - `vision`: collects only `tests/integration/inference/test_vision_inference.py`; defaults `--vision-model=ollama/llama3.2-vision:11b`, `--embedding-model=sentence-transformers/all-MiniLM-L6-v2`.
-- Explicit flags always win. For example, `--suite=responses --text-model=<X>` overrides the suite’s text model.
+  - `base`: collects most tests (excludes responses and post_training)
+  - `responses`: collects tests under `tests/integration/responses` (needs strong tool-calling models)
+  - `vision`: collects only `tests/integration/inference/test_vision_inference.py`
+- `--setup`: global configuration that can be used with any suite. Setups prefill model/env defaults; explicit CLI flags always win.
+  - Available setups:
+    - `ollama`: Local Ollama provider with lightweight models (sets OLLAMA_URL, uses llama3.2:3b-instruct-fp16)
+    - `vllm`: VLLM provider for efficient local inference (sets VLLM_URL, uses Llama-3.2-1B-Instruct)
+    - `gpt`: OpenAI GPT models for high-quality responses (uses gpt-4o)
+    - `claude`: Anthropic Claude models for high-quality responses (uses claude-3-5-sonnet)
 
-Examples:
+Examples
 
 ```bash
-# Fast responses run with defaults
-pytest -s -v tests/integration --stack-config=server:starter --suite=responses
+# Fast responses run with a strong tool-calling model
+pytest -s -v tests/integration --stack-config=server:starter --suite=responses --setup=gpt
 
-# Fast single-file vision run with defaults
-pytest -s -v tests/integration --stack-config=server:starter --suite=vision
+# Fast single-file vision run with Ollama defaults
+pytest -s -v tests/integration --stack-config=server:starter --suite=vision --setup=ollama
 
-# Combine suites and override a default
-pytest -s -v tests/integration --stack-config=server:starter --suite=responses,vision --embedding-model=text-embedding-3-small
+# Base suite with VLLM for performance
+pytest -s -v tests/integration --stack-config=server:starter --suite=base --setup=vllm
+
+# Override a default from setup
+pytest -s -v tests/integration --stack-config=server:starter \
+  --suite=responses --setup=gpt --embedding-model=text-embedding-3-small
 ```
 
 ## Examples
@@ -127,14 +135,13 @@ pytest tests/integration/
 ### RECORD Mode
 Captures API interactions for later replay:
 ```bash
-LLAMA_STACK_TEST_INFERENCE_MODE=record \
-pytest tests/integration/inference/test_new_feature.py
+pytest tests/integration/inference/test_new_feature.py --inference-mode=record
 ```
 
 ### LIVE Mode
 Tests make real API calls (but not recorded):
 ```bash
-LLAMA_STACK_TEST_INFERENCE_MODE=live pytest tests/integration/
+pytest tests/integration/ --inference-mode=live
 ```
 
 By default, the recording directory is `tests/integration/recordings`. You can override this by setting the `LLAMA_STACK_TEST_RECORDING_DIR` environment variable.
@@ -155,15 +162,14 @@ cat recordings/responses/abc123.json | jq '.'
 #### Remote Re-recording (Recommended)
 Use the automated workflow script for easier re-recording:
 ```bash
-./scripts/github/schedule-record-workflow.sh --test-subdirs "inference,agents"
+./scripts/github/schedule-record-workflow.sh --subdirs "inference,agents"
 ```
 See the [main testing guide](../README.md#remote-re-recording-recommended) for full details.
 
 #### Local Re-recording
 ```bash
 # Re-record specific tests
-LLAMA_STACK_TEST_INFERENCE_MODE=record \
-pytest -s -v --stack-config=server:starter tests/integration/inference/test_modified.py
+pytest -s -v --stack-config=server:starter tests/integration/inference/test_modified.py --inference-mode=record
 ```
 
 Note that when re-recording tests, you must use a Stack pointing to a server (i.e., `server:starter`). This subtlety exists because the set of tests run in server are a superset of the set of tests run in the library client.