A composition-derived template now stores its contained name — the
composition slot's InstanceName (e.g. "Pump"), unique only within its
owner — instead of the dotted global path ("Motor Controller.Pump").
The qualified hierarchical name is computed on read.
- TemplateNaming.QualifiedName: walks the OwnerCompositionId chain to
build the dotted path; null-safe, cycle-guarded.
- TemplateConfiguration: the unique index on Template.Name becomes
filtered (WHERE IsDerived = 0) — base templates stay globally unique;
derived templates' uniqueness is the existing (TemplateId,
InstanceName) index on TemplateComposition.
- Migration ContainedDerivedTemplateNames: rewrites derived rows to the
contained name; Down rebuilds the dotted names via a recursive CTE
before restoring the global index.
- TemplateService: composition create/rename store the contained name;
the dotted-name collision pre-checks and cascade-rename are removed
(a slot rename no longer touches nested derived templates).
- TemplateEdit: title shows the contained name; the qualified path is a
breadcrumb subtitle; "composed inside" uses the owner's qualified name.
TDD: 4 TemplateNaming tests + updated composition tests. TemplateEngine
293, ConfigurationDatabase 114, CentralUI 316 green. Migration applied to
the dev cluster and verified in the browser (Motor Controller.Pump now
titled "Pump"; nested Motor Controller.Pump.TempSensor resolves).
Design: docs/plans/2026-05-18-contained-template-names-design.md
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