fix(flow-producer): reject deduplication and debounce options (#2780)

[mohanrajvenkatesan23-04]

Why

FlowProducer.add() and addBulk() silently dropped opts.deduplication / opts.debounce. A dedup hit returns the existing job's id rather than the freshly generated one, which orphans the flow's children — there is no safe way to reconcile the two ids inside the multi-exec transaction.

Per maintainer @roggervalf on #2780:

"actually this won't work for a root parent either using flow producer because the parent ids should be known in each addition before running the transaction. Dedup logic can retrieve a different id than the one being generated from the producer."
"this functionality is not supported... We should throw an error in this case."

Closes #2780.

What

• src/classes/flow-producer.ts: file-private assertNoDeduplication(flow) helper called at the top of add() and addBulk(). Throws a clear error naming the offending queue/job.
• tests/flow.test.ts: three regression tests covering deduplication on add(), debounce on add(), and deduplication mixed into addBulk().

I left the FlowJob type alone for now — removing debounce/deduplication from the root type would be a TypeScript breaking change that warrants a separate decision. The runtime check covers JS users and any TS escape hatch.

Test plan

• tests/flow.test.ts adds three new cases under "when deduplication or debounce is provided to a flow"
• CI runs the existing flow test suite against redis@7-alpine, valkey@8, and dragonflydb@latest