Backfill normalized agent names and add owner-scoped uniqueness #192

Delivered

Agent.NormalizedName uses trimmed Unicode Form KC plus invariant uppercase. New identity names validate both display and normalized lengths. A unique filtered database index on (OwnerId, NormalizedName) protects concurrent new and renamed Agents while allowing the explicit legacy-review transition.

At application startup, unique legacy names are backfilled with the exact application normalizer. Any actual legacy collision remains unchanged and owner-reviewable rather than blocking deployment or silently renaming data. The migration is additive and rollbackable; Agent, credential, task, memory, permission, and provenance IDs are untouched.

Evidence

Commit 580f8b8 deployed successfully. Focused tests prove same-owner normalized conflicts, cross-owner reuse, and concurrent create/rename protection. Full ProjectMemory.Web.Tests result: 62 passed, 0 failed.