Module handler 

Exists command handler implementation

Purpose: Check whether an environment exists

This handler checks whether an environment with the given name exists in the data directory. It is a read-only operation that does not modify any state or make any network calls.

Design Rationale

• “Not found” is a valid result (exists = false), NOT an error
• Only repository access failures produce errors
• Returns a simple boolean result via ExistsResult

Structs

ExistsCommandHandler

ExistsCommandHandler checks whether an environment exists

ExistsResult

Result of checking whether an environment exists