Minor fixes and a smarter import flow.

What's new

• XLSX template downloads. The import wizard now generates Excel templates directly — no more CSV wrangling. Headers are prefixed with attr_ to avoid collisions, and columns sort themselves sensibly.

Improvements & fixes

• Fixed crashes when XLSX generation failed or returned incomplete files.

• Import templates now include data validation. Less room for creative interpretations of what belongs in each field.

• Unit preferences now respect entity-level settings. The hierarchy actually works the way you'd expect.

• File upload service reliability stability improvements; making the service less error prone and resiliant to crashes for long lived sockets.