🐛 fix: merge conflicting core migration leaf nodes (0040/0041)

[jc99k]

PR #283 (0040_metered_usage_record) and PR #295
(0040_auto_20260623_0025 → 0041_auto_20260623_0041) both branched off
0039_userprofile, leaving two leaf nodes in the core migration graph.
Add the merge migration so migrate has a single graph to apply.

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