fix(inverter): hold software-controlled charging after target overshoot

[Jeff-Bond-UK]

When an inverter without native target-SoC control overshoots its charge target between Predbat updates, adjust_charge_immediate() calls charge_stop_service. If that service restores self-consumption, the battery supplies the house until it falls below target and charging starts again. Reaching the target exactly already selects the configured freeze service.

This change tries charge_freeze_service in the existing non-native, above-target branch, retaining charge_stop_service when no freeze service is configured. Native target-SoC control, exact-target handling, explicit freeze handling and discharge/export control keep their existing behaviour.

Hardware evidence

Tested by the reporter on Anker SOLIX Solarbank 4 E5000 Pro with Predbat v9.3.8 and reserve control disabled. Log timestamps are Europe/London, 13 October 2026:

• 04:35: charging at 2,500 W, reported SoC 19%, target 20%.
• 04:40: SoC 22%, target 20%; the patched branch invokes the freeze service to set battery power control to 0 W. Subsequent telemetry reports battery power 0 W.
• 04:45–04:50: SoC remains 22%, battery power 0 W, Hold charging.
• 04:50: the plan moves to explicit Freeze charging; the battery remains at 22%.
• 12:05–13:25: explicit Freeze charging remains at 22%, battery power approximately 0 W.
• 13:30: the next charge period requests 2,500 W normally.

Only the above-target Hold charging behaviour changes in this PR. Explicit freeze observations demonstrate continued operation.

Validation

• New regression case fails against the unchanged upstream overshoot branch, then passes with this patch.
• Tests cover above-target charging with and without a freeze service, native-target compatibility, exact-target legacy behaviour, below-target charging, explicit freeze and its fallback, charge termination, and repeated-call deduplication.
• Inverter and execution suites pass.
• Ruff, Black, trailing-whitespace, end-of-file and export-limit-encoding hooks pass on the changed files; git diff --check passes.
• The full pre-commit command could not finish because npm rejected the markdownlint hook's local Git-package installation (EALLOWGIT). No hook configuration was changed.
• The full --quick suite passes: all tests passed, four slow tests skipped, total time 505.20 seconds.

[Jeff-Bond-UK]

@springfall2008, my Reviewers control is disabled on this PR. Could you formally request a review from a maintainer, or review it yourself please?
Thank you.