refactor(prompts): unify action schema & optimize trading discipline

## Core Changes

### 1. adaptive.txt - Adopt v5.5.6.1 strict strategy
- Migrate from dual-strategy system to unified adaptive approach
- Maintain strict confidence threshold ≥85 (anti-overtrading)
- Remove complex market state detection, focus on signal quality
- Explicitly disable partial_close (full exit only)
- -160 lines (removed redundant strategy logic)

### 2. nof1.txt - Fix contradictions & align standards
- ✅ Fix: Remove "NO partial exits" contradiction (now explicitly supported)
- ✅ Unify: Change confidence threshold from 60 → 75
- ✅ Unify: Change risk-reward ratio from 2:1 → 3:1
- Add confidence level guidance (75-85: good, 85-100: high)
- +85 lines (enhanced risk management framework)

### 3. default.txt - Add standardized output format
- Add structured thinking summary format
- Add comprehensive JSON schema documentation
- Add required fields rules for all action types
- +36 lines (improved contract clarity)

## Action Schema Migration

All prompts now use unified action naming:
- ✅ open_long / open_short (was: buy_to_enter / sell_to_enter)
- ✅ close_long / close_short (was: close)
- ✅ update_stop_loss / update_take_profit (new)
- ✅ partial_close (new, nof1 only)
- ✅ hold / wait (unchanged)

## Confidence Scale Migration

- ✅ Changed from 0-1 float to 0-100 integer across all prompts
- ✅ Opening threshold: adaptive=85, nof1=75, default=75
- ✅ Prevents overtrading through strict quality control

## Risk-Reward Standardization

- ✅ Minimum RR ratio: 1:3 across all prompts
- ✅ Replaces previous 1:2 requirement in nof1.txt

## Breaking Changes

- Backend must support new action names
- Confidence field now expects integer 0-100 (not float 0-1)
- partial_close action available in nof1.txt only

## Prompt Positioning

- **adaptive.txt**: Strict strategy (conf≥85, RR≥1:3, no partial exits)
- **nof1.txt**: English framework (conf≥75, RR≥1:3, supports partial_close)
- **default.txt**: Balanced CN strategy (conf≥75, RR≥1:3)

Related: feature/partial-close-dynamic-tpsl

Author: the-dev-z