The replacementScope of a strategy has no effect

[jzonthemtn]

FilterService._apply_strategies and _apply_replacements consult the context cache for every span regardless of the strategy's replacementScope, so DOCUMENT scope is not distinguishable from CONTEXT and the setting has no effect.

Acceptance Criteria

• replacementScope selects between document-scoped and context-scoped caching.
• The default matches the schema and the Java engine.

[jzonthemtn]

Closes a gap against the PhiSQL specification. No RFC: replacementScope is on $defs.baseFilterStrategy.