fix(car): clamp num_cars to supported maximum, exclude suspended Octopus devices

[springfall2008]

Summary

• Predbat only supports 4 cars (car_charging_rate/_1/_2/_3 in CONFIG_ITEMS, KERNEL_MAX_CARS=4 in the prediction kernel), but num_cars had no upper bound - an Octopus account with more than 4 registered Intelligent devices auto-bumped num_cars past that limit with no clamp.
• Car indices beyond 4 have no car_charging_rate_N config entity, so get_car_charging_planned() crashed every cycle with TypeError: float() argument must be a string or a real number, not 'NoneType' once triggered.
• automatic_config()'s device auto-discovery also counted suspended (e.g. decommissioned/replaced) chargers as active cars, inflating num_cars further for accounts with old devices still linked.

Changes

• Added PREDBAT_MAX_CARS = 4 to const.py as the single source of truth (also used by prediction_kernel.py's KERNEL_MAX_CARS, replacing the previously duplicated literal).
• fetch_config_options() now clamps num_cars to PREDBAT_MAX_CARS regardless of where it came from (apps.yaml, HA override, or auto-discovery), logging a warning and recording status so the clamp is visible rather than silent.
• OctopusAPI.automatic_config() now excludes devices with suspended: True from both the entity lists (octopus_intelligent_slot/ready_time/charge_limit) and the num_cars auto-bump.
• Added regression tests: a num_cars clamp test in test_fetch_config_options.py, and a new test_octopus_automatic_config_num_cars in test_octopus_misc.py covering suspended-device filtering and that auto-discovery never lowers an existing higher num_cars.
• Extended MockConfigProvider's default test config (test_infra.py) with car_charging_rate_2/_3 so tests can exercise up to the full 4-car range.

Test plan

• ./run_all --test fetch_config_options --test octopus_misc - new and existing tests pass
• ./run_all --quick - full quick suite passes (59.65s, 3 slow tests skipped as usual)
• ./run_pre_commit - passes

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR hardens Predbat’s multi-car handling by enforcing the project’s 4-car ceiling and improving Octopus Intelligent device auto-discovery so decommissioned/suspended devices don’t inflate num_cars and trigger downstream crashes.

Changes:

• Introduces PREDBAT_MAX_CARS = 4 as a single source of truth and reuses it in the prediction kernel.
• Clamps num_cars during config fetch and surfaces the clamp via logs/status.
• Filters Octopus Intelligent device auto-discovery to ignore suspended devices, with regression tests for both clamp and filtering.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
apps/predbat/const.py	Adds PREDBAT_MAX_CARS constant to centralize the supported maximum.
apps/predbat/prediction_kernel.py	Replaces the duplicated KERNEL_MAX_CARS literal with PREDBAT_MAX_CARS.
apps/predbat/fetch.py	Clamps num_cars during fetch_config_options() and records a warning status when clamped.
apps/predbat/octopus.py	Excludes suspended Intelligent devices from entity lists and num_cars auto-bump.
apps/predbat/tests/test_fetch_config_options.py	Adds regression test ensuring num_cars is clamped to 4.
apps/predbat/tests/test_octopus_misc.py	Adds regression test for suspended-device filtering and non-decreasing auto-discovery behaviour.
apps/predbat/tests/test_infra.py	Extends mock default config with additional car_charging_rate_2/_3 entries to exercise up to 4 cars in tests.

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