feat: entrypoint discovery runtime

[cotovanu-cristian]

Summary

• UiPathRuntimeFactoryRegistry.get() previously always searched cwd (.) for config files like agent.json or langgraph.json, so entrypoints in subdirectories (e.g. agents/agent1/agent.json) were not auto-detected
• Added get_factory_search_path() helper that extracts the parent directory from the entrypoint path and passes it as search_path to the registry
• Applied to run, debug, and eval commands — dev, init, and server don't need it (dev/init have no entrypoint arg; server delegates to run/debug/eval)

How it works

uipath run agents/agent1/agent.json

1. get_factory_search_path("agents/agent1/agent.json") returns "agents/agent1"
2. Registry checks Path("agents/agent1") / "agent.json" — exists — selects AgentsRuntimeFactory
3. The full entrypoint "agents/agent1/agent.json" is still passed unchanged to factory.new_runtime()

For root-level entrypoints (agent.json, main.py:main), the search path resolves to "." — no behavior change.