fix(easee_cloud): stop reporting an old change time for steady power

[frahlg]

Problem

Easee records an observation only when its value changes. easee_cloud.lua passed observation 120's timestamp (TotalPower) as power_observed_at. So while a car charged at a steady current, the reported power looked older and older, although every 5-second poll confirmed it. The old comment assumed updates at least every two minutes; the owner's box showed power unchanged for up to 5.5 minutes.

FTW treats a non-zero power reading older than power_max_age_s (180 s) as stale, and until srcfl/ftw#1417 it stood the charger down to 0 A. On the owner's home box (Tesla, Easee Home) that produced 31 stops overnight; 23 of them came 170–190 s after the last power change.

Change (easee_cloud 1.3.2 → 1.3.3)

• Unchanged value: when TotalPower is unchanged since the previous poll, the driver omits power_observed_at. FTW then stamps the reading when it arrives (ev_observation.go: PowerAt = r.UpdatedAt when the field is absent).
• New value: still carries Easee's source time, so energy accounting keeps the moment the power changed.
• Offline charger: op_mode 0 still makes get_observations fail, and the driver emits no sample.
• No clock arithmetic in Lua: the 32-bit harness (LUA_32BITS) cannot hold epoch milliseconds exactly. A first attempt that formatted host.millis() as ISO time was 42 s off there.
• Also updated: the manifest, index, devices and support status are regenerated by make check, and there is a CHANGELOG entry.

This changes telemetry timing, not control commands.

Tests

• New drivers/tests/lua_harness/test_easee_cloud_power_time.lua, run by test_easee_cloud_power_time.py:
  • a new value keeps its source time;
  • an unchanged value omits it;
  • a changed value carries the new time;
  • an offline charger emits no sample.
• test_easee_cloud_session.lua: unchanged and passing. Its assertion on the first poll's source time still holds.
• make test-driver ID=easee_cloud: 38 passed.
• make check: passes, with 88 manifests checked and 0 errors.

FTW needs a pin move afterwards to bundle 1.3.3.

🤖 Generated with Claude Code

https://claude.ai/code/session_01MuerPFZFG88kgu8sWVHeq7

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-25T04:47:18.767773Z	b4d4d18	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.