Bug: steering injection pulls from Queue-immediacy items; DefaultInputQueue should default to Immediate #49

Two related bugs

Bug 1 — ToolResultSteeringMiddleware drains Queue-immediacy items it should not touch

ToolResultSteeringMiddleware.InjectQueuedIfToolResult currently calls:

while (this.queueManager.TryDequeueNextImmediateOrQueued(out var item))

TryDequeueNextImmediateOrQueued consumes items from both Immediate and Queue-immediacy queues. Steering injection at a tool-result boundary should only ever pull Immediate items. Queue-immediacy items are semantically "hold this until the current run completes and submit as the next independent turn"; pulling them mid-run via the steering path bypasses that intent.

The correct call is the already-existing method:

while (this.queueManager.TryDequeueNextImmediate(out var item))

Affected file: Phantom.Workspaces.Llm.Core/ToolResultSteeringMiddleware.cs (line 82)

Bug 2 — DefaultInputQueue is created with Immediacy = Queue instead of Immediate

In AgentChatQueueManager:

var defaultQueue = new AgentInputQueue(
    new AgentInputQueue.Parameters
    {
        Priority = int.MaxValue - 1,
        Immediacy = AgentInputQueueImmediacy.Queue,   // ← wrong
    });

Normal user text typed into the chat input goes to DefaultInputQueue (via AgentChat.EnqueueUserMessage → DefaultInputQueue). The expected UX is that a message sent while the agent is in the middle of a tool loop gets injected at the next tool-result boundary as steering — i.e., Immediate semantics. With Queue semantics it would not be consumed by TryDequeueNextImmediate at all (and after fixing Bug 1, it also would not be consumed by steering injection even with the old TryDequeueNextImmediateOrQueued).

Fix: change the default immediacy to Immediate:

Immediacy = AgentInputQueueImmediacy.Immediate,

Users who want to explicitly hold a message until the current run finishes can use a Queue- or Held-immediacy queue explicitly; that should not be the default.

Summary of fix

AgentInputQueueManager.TryDequeueNextImmediate already exists and is the correct method — no new API is needed.