Align production nullability with the Hibernate mapping #93

Production nullability differs from the Hibernate reference. Hibernate ddl-auto=validate still starts. These rows are INFO, not PROBLEM.

Measured 2026-10-19 with bash tools/scripts/compare-schema-drift.sh both --against jpa --fail-on none.

Postgres:

• STM_APP.APP_CREATED NO vs reference YES
• STM_APP.APP_LAST_UPDATE NO vs reference YES
• STM_APP.APP_TYPE YES vs reference NO [validated_not_null]
• STM_APP.APP_UNAVAILABLE NO vs reference YES [java_default='false']
• STM_CODELIST.COD_DESCRIPTION NO vs reference YES
• STM_CODELIST.COD_SYSTEM NO vs reference YES
• STM_CONNECT.CON_DRIVER NO vs reference YES [validated_not_null]
• STM_GEOINFO.GEO_SERID YES vs reference NO
• STM_PAR_APP.PAP_APPID YES vs reference NO
• STM_PAR_SER.PSE_TYPE YES vs reference NO [validated_not_null]
• STM_PAR_SER.PSE_VALUE NO vs reference YES [validated_not_null]
• STM_STY_GI.SGI_GIID YES vs reference NO
• STM_TOKEN_USER.ACTIVE NO vs reference YES
• STM_TOKEN_USER.EXPIRE_AT YES vs reference NO
• STM_TREE_NOD.TNO_ACTIVE YES vs reference NO [java_default='true']
• STM_TSK_TYP.TTY_ENABLED NO vs reference YES

Oracle has the same rows except it does not list STM_CODELIST.COD_DESCRIPTION, STM_PAR_SER.PSE_TYPE, or STM_PAR_SER.PSE_VALUE, and it adds:

• STM_APP.APP_NAME YES vs reference NO
• STM_AVAIL_GI.AGI_GIID YES vs reference NO
• STM_AVAIL_GI.AGI_TERID YES vs reference NO
• STM_TREE_NOD.TNO_LOAD_DATA YES vs reference NO [java_default='false']