chore(release): reconcile main ancestry for v0.5.6

[mohanagy]

Summary\n\nReconcile the v0.5.5 main promotion merge into development before the v0.5.6 promotion.\n\nThis merge commit has two parents:\n\n- current development at 6bd03f7\n- current main and v0.5.5 at c7faca2\n\nThe resulting tree is byte-for-byte identical to its development parent. There are no source, documentation, dependency, package, workflow, or generated-file changes.\n\nTracks #327.\n\n## Security impact\n\nNone. The tree is unchanged from the already reviewed and tested development head, so credential handling, routing, policy, redaction, audit, subprocess, dependency, failure, POSIX, and Windows boundaries are identical.\n\n## Validation\n\n- [x] HEAD tree equals the first-parent development tree.\n- [x] git diff HEAD^1 HEAD is empty.\n- [x] current main is an ancestor of this merge commit.\n- [x] The identical development tree passed the complete local release gate set and PR #328 cross-platform CI.\n- [x] No credentials, private data, dependencies, or packaged files changed.\n\nThis PR must be merged with a merge commit, not squash or rebase, so the main ancestry parent is preserved.

[mohanagy]

Final exact-head evidence for e2b3a3d:\n\n- independent review: CLEAN; exact parents, identical tree, and ancestry preservation verified\n- tree equals development parent 6bd03f7 exactly; diff is empty\n- current main c7faca2 is an ancestor of the head\n- Linux, macOS, Windows Node 20/22/24, Linux quality, Verify, and CodeRabbit checks all passed\n- no unresolved review threads\n\nThis PR must be merged with merge_method=merge so the ancestry parent is retained.