Add mower progress to StatsEvent

[monsivar]

Summary

Add support for mowing job progress statistics reported by GOAT mowers, with the behavior enabled explicitly for the GOAT O1200 LiDAR (2i0fns).

For the O1200, observed stats semantics are:

• area: planned total mowing area
• mowedArea: area mowed so far
• time: estimated total mowing duration

This change preserves compatibility for existing devices while exposing the additional data needed by consumers to calculate mowing progress.

Changes

• Add optional keyword-only StatsEvent.mowed_area
• Parse mowedArea from onStats
• Parse mowedArea from GetStats
• Add CapabilityStats.mowing_job_progress, defaulting to False
• Enable mowing_job_progress only for hardware class 2i0fns
• Keep existing mower models such as 5xu9h3 on their current stats semantics
• Add focused command/message and hardware capability tests

Consumers can derive progress for devices with mowing_job_progress=True as:

mowed_area / area * 100

Verification

Observed on a GOAT O1200 LiDAR during a mowing job:

• area=492475 -> 49.2475 m² planned area
• mowedArea=28699 -> 2.8699 m² mowed
• progress ≈ 5.83%, shown as 6% in the Ecovacs app
• time=2304 -> 38m24s estimated total mowing duration

Relevant stats and hardware tests pass locally.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.31%. Comparing base (5453eba) to head (95c4491).

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1771      +/-   ##
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+ Coverage   96.26%   96.31%   +0.04%     
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  Files         161      161              
  Lines        6399     6401       +2     
  Branches      368      368              
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+ Hits         6160     6165       +5     
+ Misses        172      169       -3     
  Partials       67       67              

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[codspeed]

Merging this PR will not alter performance

✅ 226 untouched benchmarks

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_{Comparing monsivar:feature/mower-stats-progress (95c4491) with dev (5453eba)}

[monsivar]

Downstream Home Assistant implementation is now available as a draft PR for visibility and dependency tracking: home-assistant/core#180054

It intentionally remains in draft until this PR is merged and included in a published deebot-client release. At that point the HA branch can bump the dependency, run final validation against the released client version, and be marked ready for review.

[edenhaus]

Suggested change

	area=data.get("area"),
	area=data.get("area", data.get("mowedArea")),

I expect area is not there if mowedArea is there. So this one would be just falling back the mowedArea when area is not available

[monsivar]

On the O1200 both fields are present in the same onStats payload. In the capture used for this PR, area=492475 is the planned total area, while mowedArea=28699 is the area completed so far. So mowedArea is not a fallback for area on this device; they represent different values. That's why I kept them separate. I can add the captured payload shape to the test if that would make the distinction clearer.