README: clarify viewer table scope (curated main file; legacy archive separate)

README.md

@@ -39,7 +39,7 @@ ds = load_dataset("kelikelibababian/mimir-agent-traces", split="train")
 print(ds[0])          # one row = one complete agent session
 ```
 
-The viewer table is served as **Parquet** (`data/train.parquet`) — a unified-schema view over the append-only JSONL source (`data/mimir-agent-traces.jsonl`, which is kept as-is and never rewritten). Rows uploaded before schema v2 carry `null` in the seven v2-only columns, so the whole corpus loads as a single table.
+The viewer table is served as **Parquet** (`data/train.parquet`) — a unified-schema view over the append-only JSONL source (`data/mimir-agent-traces.jsonl`, which is kept as-is and never rewritten). It covers the **curated main file (4,168 sessions)**; the larger pre-filter archive is kept separately as `data/mimir-agent-traces-legacy-full.jsonl` and is **not** part of this table. Rows uploaded before schema v2 carry `null` in the seven v2-only columns, so the curated corpus loads as a single table.
 
 ## What's inside