feat(agents): add agent naming functionality (#1922)

# What does this PR do?
Allow users to name an agent and use the name in telemetry instead of
relying on randomly generated agent_ids. This improves the developer
experience by making it easier to find specific agents in telemetry
logs.

Closes #1832

## Test Plan

- Added tests to verify the agent name is properly stored and retrieved
- Ran `uv run -- pytest -v
tests/integration/telemetry/test_telemetry.py::test_agent_name_filtering`
from the root of the project and made sure the tests pass
- Ran `uv run -- pytest -v
tests/integration/telemetry/test_telemetry.py::test_agent_query_spans`
to verify existing code without agent names still works correctly

## Use Example
```
agent = Agent(
    llama_stack_client, 
    model=text_model_id, 
    name="CustomerSupportAgent",  # New parameter
    instructions="You are a helpful customer support assistant"
)
session_id = agent.create_session(f"test-session-{uuid4()}")
```

## Implementation Notes
- Agent names are optional string parameters with no additional
validation
- Names are not required to be unique - multiple agents can have the
same name
- The agent_id remains the unique identifier for an agent

---------

Co-authored-by: raghotham <raghotham@gmail.com>

docs/_static/llama-stack-spec.html

@@ -5221,17 +5221,25 @@
                         "default": 10
                     },
                     "model": {
-                        "type": "string"
+                        "type": "string",
+                        "description": "The model identifier to use for the agent"
                     },
                     "instructions": {
-                        "type": "string"
+                        "type": "string",
+                        "description": "The system instructions for the agent"
+                    },
+                    "name": {
+                        "type": "string",
+                        "description": "Optional name for the agent, used in telemetry and identification"
                     },
                     "enable_session_persistence": {
                         "type": "boolean",
-                        "default": false
+                        "default": false,
+                        "description": "Whether to persist session data"
                     },
                     "response_format": {
-                        "$ref": "#/components/schemas/ResponseFormat"
+                        "$ref": "#/components/schemas/ResponseFormat",
+                        "description": "Optional response format configuration"
                     }
                 },
                 "additionalProperties": false,
@@ -5239,7 +5247,8 @@
                     "model",
                     "instructions"
                 ],
-                "title": "AgentConfig"
+                "title": "AgentConfig",
+                "description": "Configuration for an agent."
             },
             "AgentTool": {
                 "oneOf": [