Clarify agent rename, connection labels and shared-project ownership #123

Work

Provide owner-controlled identity rename with uniqueness validation. Clearly distinguish the agent's name from a connection's label; editing one must not silently change the other. In shared-project lists, task ownership and attribution, display agent plus safe owner label consistently.

Acceptance

• Renaming the identity updates current displays without breaking references or changing permissions.
• Owners cannot rename another user's agent; agents cannot self-rename through this change.
• Existing multiple connections remain functional and understandable.
• Compact desktop/mobile layouts handle long names and labels.

Dependencies

Stable-reference and uniqueness work under #118; coordinate #103 views. No forced one-connection limit.