docs: add SETUP.MD for Agentic Inner Loop KPI

Adds the SETUP.MD required by the Agentic Inner Loop validation
pipeline (MER KPI 11). Documents prerequisites, environment setup,
build, test, and a prescribed sample code change so an AI agent
can autonomously run the inner dev loop on a clean Linux machine.

PRODEV-624

Author: giuliastf

SETUP.MD

@@ -0,0 +1,124 @@
+# SETUP.MD
+
+## Prerequisites
+
+- Python 3.11+
+- [uv](https://docs.astral.sh/uv/) 0.5+
+
+### Supported platforms
+
+This checklist controls the Agentic Inner Loop KPI pipeline targets (clean Linux VM). The repo's own GitHub Actions CI additionally tests on `windows-latest`, but that is not measured by this KPI.
+
+- [x] Linux
+- [ ] Windows
+- [ ] macOS
+
+## Environment Variables
+
+### Standard (injected by pipeline)
+
+None of the standard pipeline variables are required for environment setup, build, or unit tests.
+
+### Project-specific
+
+None. The unit-test suites under the `Test` section below run fully offline and require no external authentication.
+
+## Setup
+
+```bash
+# Install uv if not already on PATH (no-op when pre-installed by the pipeline)
+python3 -m pip install --upgrade uv
+
+# Sync all five packages with dev dependencies (each is independent)
+uv --directory packages/uipath-agent-framework sync --all-extras
+uv --directory packages/uipath-google-adk sync --all-extras
+uv --directory packages/uipath-llamaindex sync --all-extras
+uv --directory packages/uipath-openai-agents sync --all-extras
+uv --directory packages/uipath-pydantic-ai sync --all-extras
+```
+
+## Verify Setup
+
+```bash
+python3 --version
+uv --version
+uv --directory packages/uipath-agent-framework run python -c "import uipath_agent_framework; print('uipath-agent-framework ok')"
+uv --directory packages/uipath-google-adk run python -c "import uipath_google_adk; print('uipath-google-adk ok')"
+uv --directory packages/uipath-llamaindex run python -c "import uipath_llamaindex; print('uipath-llamaindex ok')"
+uv --directory packages/uipath-openai-agents run python -c "import uipath_openai_agents; print('uipath-openai-agents ok')"
+uv --directory packages/uipath-pydantic-ai run python -c "import uipath_pydantic_ai; print('uipath-pydantic-ai ok')"
+```
+
+## Build
+
+```bash
+uv --directory packages/uipath-agent-framework build
+uv --directory packages/uipath-google-adk build
+uv --directory packages/uipath-llamaindex build
+uv --directory packages/uipath-openai-agents build
+uv --directory packages/uipath-pydantic-ai build
+```
+
+## Test
+
+```bash
+uv --directory packages/uipath-agent-framework run pytest
+uv --directory packages/uipath-google-adk run pytest
+uv --directory packages/uipath-llamaindex run pytest
+uv --directory packages/uipath-openai-agents run pytest
+uv --directory packages/uipath-pydantic-ai run pytest
+```
+
+## Sample Code Change
+
+### The change
+
+Add a new `agent_count` property to `PydanticAiConfig` in `packages/uipath-pydantic-ai/src/uipath_pydantic_ai/runtime/config.py`, immediately after the existing `entrypoint` property:
+
+```python
+@property
+def agent_count(self) -> int:
+    """Number of agents defined in the configuration."""
+    return len(self.agents)
+```
+
+Then create `packages/uipath-pydantic-ai/tests/test_config_agent_count.py` with two pytest tests:
+
+```python
+"""Tests for PydanticAiConfig.agent_count."""
+
+import json
+from pathlib import Path
+
+from uipath_pydantic_ai.runtime.config import PydanticAiConfig
+
+
+def test_agent_count_single(tmp_path: Path) -> None:
+    config_path = tmp_path / "pydantic_ai.json"
+    config_path.write_text(json.dumps({"agents": {"main": "main:agent"}}))
+    cfg = PydanticAiConfig(str(config_path))
+    assert cfg.agent_count == 1
+
+
+def test_agent_count_multiple(tmp_path: Path) -> None:
+    config_path = tmp_path / "pydantic_ai.json"
+    config_path.write_text(
+        json.dumps(
+            {
+                "agents": {
+                    "alpha": "alpha:agent",
+                    "beta": "beta:agent",
+                    "gamma": "gamma:agent",
+                }
+            }
+        )
+    )
+    cfg = PydanticAiConfig(str(config_path))
+    assert cfg.agent_count == 3
+```
+
+### Verification
+
+```bash
+uv --directory packages/uipath-pydantic-ai run pytest tests/test_config_agent_count.py -v
+```