fix(enphase): delete schedules via POST /<id>/delete, not the DELETE verb

[springfall2008]

Follow-up to #4428, which shipped the schedule-conflict fix but used the wrong delete endpoint.

Problem

The schedule cleanup in #4428 issued DELETE /battery/sites/<site>/schedules/<id>. The BatteryConfig gateway does not allow that verb on the resource and rejects it:

DELETE /service/batteryConfig/api/v1/battery/sites/5667604/schedules/9440ae1e-... -> 403 Invalid CORS request

The API exposes deletion as POST /schedules/<id>/delete — as the integration design notes in docs/superpowers/specs/2026-07-11-enphase-cloud-integration-design.md already recorded. The headers were never the problem: Origin/Referer are set for the battery_config family, and GET/PUT on the same base path succeed in the same session with the same headers. Only the verb differed.

In a 15-minute deployed log: 28 delete attempts, all 403, zero successes.

Two consequences:

• A window Predbat wanted to retire was never cleared, so the disable path retried it on every cycle and never converged.
• A 403 counts as an auth failure in request_json, so each failed delete also burned a re-login — six Enphase logins in fifteen minutes, against an account that rejects excess sessions. (LOGIN_REUSE_SECONDS = 30 bounded it, and no rejection or suspension was reached, but the churn is unnecessary.)

What #4428 did fix

Same log, same site: zero CONFLICTING_SCHEDULE_* errors, down from 272 in 13 hours. The id-pinning and conflict-retry changes are working; only the delete verb was wrong.

Changes

• _delete_schedule now POSTs to the /delete sub-resource.
• Tests updated to assert the exact method and path, plus a new focused test (test_delete_schedule_posts_to_the_delete_endpoint) that pins the endpoint so this cannot regress silently.

Written test-first; the new test failed against the DELETE-verb implementation before the fix. ./run_pre_commit passes — all hooks green, full quick suite green.

Version bumped v8.47.4 → v8.47.5.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes Enphase schedule cleanup by switching schedule deletion from the unsupported DELETE /.../schedules/<id> to the API-supported POST /.../schedules/<id>/delete, preventing persistent 403s and the resulting re-login churn in the Enphase BatteryConfig gateway path.

Changes:

• Update EnphaseAPI._delete_schedule() to POST to the /delete sub-resource (with allow_empty=True to accept 204/no-body success).
• Update and extend Enphase API tests to assert the correct delete endpoint/method and prevent regression.
• Bump Predbat version v8.47.4 → v8.47.5.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
apps/predbat/enphase.py	Switch schedule deletion to POST .../schedules/<id>/delete and document why (gateway rejects DELETE).
apps/predbat/tests/test_enphase_api.py	Add a focused regression test for the POST delete endpoint; update existing tests to match the new delete behavior.
apps/predbat/predbat.py	Version bump to v8.47.5.