MCP: match flock names case-insensitively, like grades and the flock search #1228

Part of #789. Found in the MCP audit.

Problem

The same model-supplied name is matched three ways:

• cluckwork_list_flocks nameContains:"barn a" finds "Barn A" (ILike, FlockRepository.cs:75).
• grade:"large" matches "Large" (OrdinalIgnoreCase, DailyEntryTools.cs and StockTools.cs).
• flock:"barn a" on cluckwork_list_daily_entries and cluckwork_record_daily_entry answers No flock you can see is named or numbered 'barn a'. because ListByNameAsync compares f.Name == name (FlockRepository.cs:130).

Models often lower-case names they copy from a person's message. The refusal uses the same wording as a Worker's scope refusal, so it reads like a permission problem.

A related inconsistency: CommerceTools.cs echoes an unknown status value back, while FlockTools.cs deliberately does not, for the reason REST gives (log-visible control characters). Pick one rule.

Fix

• Compare lower(Name) in ListByNameAsync. The existing ambiguity refusal already covers two flocks that differ only in case.
• Drop "exact" from the flock parameter descriptions.
• Make the status echo consistent.

Acceptance

flock:"barn a" resolves "Barn A". Two flocks named "Barn A" and "barn a" give the ambiguity refusal.