Class GraphProviderPool

Release graphs in this batch that are done. Host mode: frees the host for the next graph (the push transaction settles it later). Independent mode: commit-or-rollback + release the graphs whose last level is levelIndex, or whose TransactionDepth is already 0. Returns the first settle error so the caller cannot report success with uncommitted rows.

One record error anywhere in the file rolls back every graph in that file.

Record, per graphId, the highest dependency-level index it occupies so we can drain (commit/rollback + release) as soon as that level finishes.

Provider for this graph. See the class comment for the per-mode rules.

Release every remaining graph. Safe to call from finally.