Clean Thingifier DDD and HTTP boundaries

[eviltester]

Summary

• split repository/store responsibilities and keep relationship cascade decisions inside repository/store boundaries
• add application command services and shared relationship parsing/resolution
• clean Spark to internal HTTP conversion with explicit internal request/response types

Verification

• mvn -pl thingifier,challenger -am verify
• mvn -pl challengerAuto -am test "-Dchallenger.auto.local.repository=memory" "-DfailIfNoTests=false"
• mvn -pl challengerAuto -am test "-Dchallenger.auto.local.repository=sqlite-memory" "-DfailIfNoTests=false"

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