feat(fase-19): pipeline SHORT completo (Engine, Portfolio, RiskManager, brokers)

[guigerdts]

Summary

• Portfolio: _short_positions tracking, short liability en get_total_value
• RiskManager: SHORT/BUY-to-close approval, 3-tuple _active_entries
• Engine: Pipeline SHORT completo
• PaperBroker: Capital management para SHORT
• BinanceBroker: SHORT -> Side.SELL mapping
• 15 YAMLs de estrategias con secciones short_entry
• 38 tests nuevos

Cambios

Archivo	Cambio
risk/portfolio.py	_short_positions, short liability
risk/manager.py	SHORT/BUY-to-close, _active_entries 3-tuple
core/engine.py	SHORT pipeline completo
execution/paper_broker.py	SHORT capital
execution/binance_broker.py	SHORT -> Side.SELL
cells/templates/*.yaml	short_entry en 15 estrategias
tests/	38 tests nuevos (risk, portfolio, engine, telegram)

Chain Context

Field	Value
Chain	FASE 19
Tracker PR	#3
Position	5 of 5
Base	feat/fase-19-pr4a-cell
Depends on	PR4A #7
Follow-up	None (ultimo)
Review budget	1,502 / 400 (tests: 671, YAMLs: 590)

Chain Overview

main
 └── #3 tracker/fase-19 (draft)
      └── #4 PR1 — Diagnostics + Drawdown
           └── #5 PR2 — TradeTracker
                └── #6 PR3 — Dashboard
                     └── #7 PR4A — Cells Bidirectional
                          └── 📍 #8 This PR — Bidirectional Completion