fix: unwrap action parameters and capture query settings in v2 protocol

[Garulf]

Problem

In the V2 (python_v2) protocol, methods registered via Result.add_action were triggered without their parameters — multi-parameter methods failed with a swallowed TypeError ("Internal error" response), and single-parameter methods received the whole parameters list as one argument. This also broke actions attached to context-menu results. Additionally, plugin.settings was never populated under V2.

Root cause

Flow Launcher's V2 host executes actions via StreamJsonRpc's single-argument overload:

RPC.InvokeAsync<JsonRPCExecuteResponse>(result.JsonRPCAction.Method, argument: result.JsonRPCAction.Parameters);

That overload wraps the entire Parameters list in a one-element array, so the wire message is "params": [["a", "b"]] — unlike V1's "parameters": ["a", "b"]. FlowLauncherV2.run passed it straight to dispatch(method, *params), giving the method one list argument instead of its unpacked parameters.

Settings are sent by the V2 host as the second query param (InvokeWithCancellationAsync("query", new object[] { query, Settings.Inner })), but only a top-level settings key was being read.

Changes

• FlowLauncherV2.run unwraps the single-element list wrapping for action methods before dispatch. context_menu is explicitly excluded (its single list argument is the ContextData, matching V1 behavior), and query keeps its existing special case.
• FlowLauncherV2.run stores params[1] of query requests as the launcher settings; the top-level settings key remains as a fallback.
• New integration tests: TestV2Actions (parameters unwrapped, empty-parameter actions, execute-response shape, context_menu V1 parity) and two TestV2Settings cases (settings captured from query params and not leaked into handler arguments).
• Ignore uv.lock.

Reapplies 342574f and fe2376e (reverted off main in 0f5d2bc/c056e77 so this lands via PR review).