docs: remove outdated pre-V3 analysis documents

Delete performance, bulk operations, concurrent access, Raft consensus, and
E2E setup analysis documents that predate the V3 state machine rewrite.
These have been superseded by the ArchitecturalAudit and
CorrectRaftStateMachinePattern documents in docs/.

Also update mix.exs to remove references to deleted documentation files
from docs.extras and package.files.

Author: GSMLG-BOT