fix(observability): desktop dev version and web environment match the other services - #23975

Eligibility
This is a focused observability metadata correction: unpackaged desktop runs report the app version, while web spans identify development versus production builds. Packaged behavior, product functionality, APIs, and deployment behavior remain unchanged, and the desktop branch has focused test coverage.

Notes:
No code owners found in target merge base a68e6e9

Agent Credits: 30 credits
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