Fix sidebar username, Signals filter clarity and layout

- JWT now carries a username claim; sidebar shows "Signed in as <name>"
  instead of the bare user id (sub). Re-login required for the new claim.
- Signals: Min R:R / Min Confidence inputs reflect the effective filter —
  auto-filled from the activation gate when "Qualified only" is on, reset
  to 0 when off (no more misleading 0 while the gate is active).
- Signals layout: Run Scanner moved to its own action row (it's a job
  trigger, not a filter); qualified toggle grouped with the refinement
  filters under one Filters panel.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/schemas/trade_setup.py

@@ -16,6 +16,7 @@ class TradeTargetResponse(BaseModel):
     classification: str
     sr_level_id: int
     sr_strength: float
+    is_primary: bool = False
 
 
 class RecommendationSummaryResponse(BaseModel):