resolveColumnName

Resolves the CQL column name for a property given the raw @Column.name argument value, or null if the property carries no @Column annotation at all.

A blank/whitespace-only @Column(name = "") is treated identically to "no @Column" and falls back to camelToSnake(propertyName) — this fallback must stay in sync between SchemaRegistry (runtime) and KandraProcessor (codegen), otherwise the same entity can resolve to two different column names depending on which one looks at it (GH-30).