[Spike] Map between stored and form addressing of a configuration

[markus-moser]

Spike — for review of the approach, not for merge as it stands. Nothing consumes ConfigurationPathMapper yet; it exists to settle a question before a review/diff surface is built on top of the configuration editor.

transformBackendToForm() is not shape-preserving, so a dotted address into the stored configuration does not name the same field in the form. Two rules cover every divergence:

1. general.active|description|group|name are lifted to the form root.
2. Mapping items are addressed by mappingId in the stored document and by list index in the form.

Everything else is the same path on both sides.

The tests document three findings that matter for anything diffing a configuration:

• The mapping is config-dependent, not a string rewrite. Resolving an item needs the document.
• It is asymmetric. An address naming a mapping item the configuration does not carry — an item some other version adds — has no form path at all, because there is no row to point at.
• mappingId is minted in the Studio form, so a configuration written before it, or by the console, carries none. Those rows are skipped rather than given a positional key, so a caller can tell the difference.

Gates

Gate	Result
PHPStan (level 5)	0 errors
php-cs-fixer	0 files to fix
Codeception unit	11 tests, 34 assertions, green

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate failed

Failed conditions
3 New Major Issues (required ≤ 0)

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