fix: Stop charging immediately in EV_FREE mode when surplus insufficient (v1.0.3)

When Priority Balancer is in EV_FREE state (both targets met), the charger
now stops immediately when surplus drops below 6A minimum, instead of waiting
for the 30-second surplus drop delay.

Rationale:
- EV_FREE is opportunistic charging only (both targets already met)
- Delays are meant for PRIORITY_EV to handle temporary fluctuations
- In EV_FREE, we should only charge when there's genuine surplus available
- No need to wait when both systems are already balanced

Technical Changes:
- Added immediate stop condition in solar_surplus.py before delay logic
- Condition: priority == PRIORITY_EV_FREE && target_amps == 0 && charger_on
- Action: Stop charger with reason 'EV_FREE: Opportunistic charging requires sufficient surplus'
- Resets all state tracking delays

Example:
- Priority: EV_FREE (both targets met)
- Surplus: 1.61A (< 6A minimum)
- Old: Continue charging, wait 30s delay
- New: Stop immediately

Updated:
- custom_components/ev_smart_charger/solar_surplus.py (immediate stop logic)
- custom_components/ev_smart_charger/manifest.json (v1.0.3)
- custom_components/ev_smart_charger/const.py (VERSION = 1.0.3)
- README.md (v1.0.3 changelog)
- CLAUDE.md (v1.0.3 version history)

Author: Antonio ...