[P1] Detect → emit → execute pipeline: end-to-end workflow automation

[JerrettDavis]

Objective

Wire the complete pipeline: prompt classifier detects workflow → WorkflowEmitter produces WorkflowFramework-compatible YAML → user confirms → WorkflowFramework executor runs deterministically.

Pipeline

User prompt
    ↓
IPromptIntentClassifier (#401) — is this a workflow?
    ↓ yes
WorkflowEmitter — LLM generates WorkflowFramework YAML
    ↓
User confirmation (approval gate)
    ↓
Bridge (#402) — translate to WorkflowFramework definition
    ↓
WorkflowFramework engine — deterministic execution
    ↓
Results streamed back via SignalR

Deliverables

• Update WorkflowEmitter to emit WorkflowFramework-compatible YAML (not JD.AI's custom format)
• System prompt/skill that directs the LLM to produce valid WorkflowFramework DSL
• Confirmation UX in TUI and Gateway API
• Execution result streaming via SignalR
• End-to-end integration test

Blocking Order

Depends on #401 (classifier), #402 (bridge), #403 (gateway API)