feat: Add auto-lock timer sensor with dashboard badge (#509)

[tykeal]

Summary

Implements the feature requested in #509 — display the auto-lock countdown timer on the Home Assistant dashboard.

Changes

New auto-lock timer sensor (sensor.autolock_timer):

• Timestamp sensor (device_class=TIMESTAMP) that shows when the auto-lock timer will fire
• Timer-emulating attributes: duration, remaining, finishes_at, is_running
• State is unknown when timer is idle, a timestamp when running
• Unavailable when lock is disconnected or autolock is disabled

Dashboard integration:

• Conditional badge added to generated Lovelace dashboard
• Badge only visible when timer is running (not unknown/unavailable)

Timer responsiveness:

• Coordinator pushes data updates immediately when timer starts/cancels
• Previously entities only saw timer state changes on the ~30-second refresh cycle

Timer state consistency:

• Refactored KeymasterTimer to use shared _cleanup_expired()/_check_expired() methods
• All property accessors now consistently clear _duration on timer expiry (previously only cancel() did)
• Sensor snapshots all timer values atomically to avoid race conditions

Bug fix — float-to-int conversion:

• HA's NumberEntity passes float values to async_set_native_value
• Autolock minute values (autolock_min_day/autolock_min_night) are typed as int but were stored as float after user modification
• This caused ValueError in the sensor's :02d format specifier, making the entity stay unknown

Testing

• 17 new tests across sensor, coordinator, lovelace, and number test files
• All 409 tests pass (excluding 2 pre-existing failures in test_init.py)

Closes #509

[Copilot]

Pull request overview

This PR implements issue #509 by exposing the auto-lock countdown as a new Home Assistant timestamp sensor and wiring it into the generated Lovelace dashboard so users can see the timer while it’s running.

Changes:

• Added sensor.autolock_timer (timestamp device class) with timer-style attributes (duration, remaining, finishes_at, is_running).
• Updated coordinator to push immediate updates when the auto-lock timer starts/cancels (instead of waiting for the periodic refresh).
• Fixed autolock minute number entities to coerce float inputs to int, and added/updated tests for the new behavior and dashboard badge.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
custom_components/keymaster/sensor.py	Adds the new auto-lock timer sensor entity and its coordinator update handling.
custom_components/keymaster/helpers.py	Extends KeymasterTimer to track duration and centralizes expiry cleanup/check logic.
custom_components/keymaster/coordinator.py	Pushes async_set_updated_data immediately after timer start/cancel for responsiveness.
custom_components/keymaster/number.py	Converts autolock minute values from float to int in async_set_native_value.
custom_components/keymaster/lovelace.py	Adds a conditional “Auto Lock Timer” badge and supports custom visibility conditions.
tests/test_sensor.py	Adds tests covering the new sensor behavior and seconds formatting helper.
tests/test_number.py	Adds parametric test verifying float-to-int conversion for autolock minute numbers.
tests/test_lovelace.py	Adds test ensuring the autolock timer badge is generated with the intended visibility conditions.
tests/test_coordinator.py	Adds tests/expectations for immediate coordinator data push on timer start/cancel.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.05%. Comparing base (cdb4922) to head (fe47550).
⚠️ Report is 46 commits behind head on main.
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #577      +/-   ##
==========================================
+ Coverage   84.14%   86.05%   +1.91%     
==========================================
  Files          10       25      +15     
  Lines         801     2804    +2003     
==========================================
+ Hits          674     2413    +1739     
- Misses        127      391     +264     

Flag	Coverage Δ
python	86.05% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[firstof9]

I'd like to see 100% patch coverage 😃

[tykeal]

I'd like to see 100% patch coverage 😃

Of course you would. So would I! ;) I'll get that fixed.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated no new comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[tykeal]

@firstof9 100% coverage on the change now :)

[firstof9]

Does "auto lock" account for the door status, if it exists?

[tykeal]

No, it doesn't. We do have a separate issue about that (#572). This is explicitly about #509 which is adding the timer to the dashboard