fix: promote dev to master

[icebear0828]

Summary

• promote the current dev tree plus fix: harden dev promotion readiness #590 promotion-readiness fixes onto master as a single linear squash commit
• resolve the master/dev divergence by taking the fixed dev tree for conflicted files
• keep the promotion commit free of merge commits for the master linear-history ruleset

Why this path

Direct dev -> master fast-forward is not viable: master and dev have diverged, and dev contains merge commits that master branch protection rejects. This branch starts from origin/master and squashes the fixed dev tree onto it.

Verification

• final promotion tree has no diff from fix/dev-master-promotion-readiness (a1459c9)
• git rev-list --count --merges origin/master..HEAD => 0
• git diff --check HEAD~1..HEAD
• npm test (239 files, 2355 passed, 1 skipped) on the matching source tree
• npm run build on the matching source tree

Pair PR

• fix: harden dev promotion readiness #590 carries the promotion-readiness fixes into dev. Merge both PRs deliberately so dev and master remain aligned at the tree level.

Notes

• Windows PowerShell smoke execution was not run locally because this machine does not have pwsh; workflow/static tests cover the wiring and script shape.