docs(lance): 9.0.0-beta.15 alignment stanza; close the vendor-pin and blob-compaction gaps

New dated audit stanza in lance.md (382 upstream commits across the 7->8
and 8->9-beta.15 legs; zero ecosystem churn, no format/reader-floor
movement, the FTS-v2 soft door, the merge_insert rewrite, the open
items #6666/#6914/#7508). invariants.md: the vendored-lance-table and
blob-column-compaction known gaps close per their documented removal
conditions. AGENTS.md: substrate line + compaction matrix row. testing.md:
the blob guard's new positive name.

docs/dev/testing.md

@@ -26,7 +26,7 @@ The engine's `tests/` is the principal coverage surface; most graph-shaped behav
 | `staged_writes.rs` | TableStore staged-write primitives (`stage_append`, `stage_merge_insert`, `commit_staged`, `scan_with_staged`, `count_rows_with_staged`) — primitive-level only; engine code uses the in-memory `MutationStaging` accumulator instead |
 | `forbidden_apis.rs` | Defense-in-depth source-walk guard: engine code (`exec/`, `db/omnigraph/`, `loader/`, `changes/`) must not reach around the sealed storage trait to Lance inline-commit APIs, nor open datasets directly (`Dataset::open` / `DatasetBuilder::from_uri`/`from_namespace`) — reads route through `Snapshot::open` and the held-handle cache; `// forbidden-api-allow: <reason>` sentinel exempts reviewed lines |
 | `failpoint_names_guard.rs` | Source-walk guard (same defense-in-depth shape as `forbidden_apis.rs`): every failpoint call site (`maybe_fail`, `ScopedFailPoint::new`/`with_callback`, `Rendezvous::park_first`) must reference a `failpoints::names` const, never a bare string literal — a typo'd literal compiles and silently never fires |
-| `lance_surface_guards.rs` | Pins the Lance API surfaces omnigraph depends on (named runtime + compile-only guards; see [lance.md](lance.md)) — the first smoke check on any Lance version bump; e.g. `compact_files_still_fails_on_blob_columns` turns red when the upstream blob-compaction fix lands |
+| `lance_surface_guards.rs` | Pins the Lance API surfaces omnigraph depends on (named runtime + compile-only guards; see [lance.md](lance.md)) — the first smoke check on any Lance version bump; e.g. `compact_files_succeeds_on_blob_columns` pins blob-v2 compaction working (a red means a Lance regression) |
 | `warm_read_cost.rs` | Cost-budget tests for the warm read path (query-latency work), measured at the object-store boundary with Lance `IOTracker` (the LanceDB IO-counted pattern): a warm same-branch read does 0 manifest opens, 1 version probe, validates the schema once (Fix 1 / finding A / Fix 2 at commit-history depth); stale same-branch reads perform exactly 2 probes and refresh manifest-only; recreated non-main branches with the same Lance version refresh by incarnation; recreated branch-owned table handles are distinguished by table e_tag or refresh-time cache clearing; recreated traversal topology is protected by per-edge-table e_tag in the graph-index cache key or refresh-time cache clearing; a warm *repeat* read does 0 table opens via the held-handle cache and a write re-opens only the changed table at its new version/e_tag (Fix 3/6A). Also the CSR topology-build cost guards: `fresh_branch_traversal_reuses_main_graph_index` (A1 — a lazy-fork branch reuses main's cached CSR index, 0 rebuilds via `graph_build_count`) and `single_edge_query_builds_only_referenced_edge` (A2 — a one-edge query builds only that edge via `graph_edges_built`); both force CSR via the scoped `with_traversal_mode` seam, so they need no `#[serial]`. See "Cost-budget tests" below. |
 | `write_cost.rs` | Cost-budget tests for the WRITE path (RFC-013), the latency twin of `warm_read_cost.rs` on the **shared `helpers::cost` harness** (`measure`/`IoCounts`/`assert_flat`/`local_graph`). Runs on **local FS**; gates the **internal-table** term (`__manifest` scans flat in commit-history depth, lineage rows included — `internal_table_scans_are_flat_in_history`, now **green every-PR** since RFC-013 step 2 brought the internal tables into `optimize`; the test compacts at each depth before measuring) plus green every-PR guards (single-insert `data_writes` bounded, a per-write read-op ceiling that fails the moment a round-trip is added, and a `measure_with_staged` fitness assert that a keyed insert routes through `stage_merge_insert` once with no `stage_append`/vector-index build). The **data-table opener** term is S3-only — see `write_cost_s3.rs` and the backend-split note in "Cost-budget tests" below |
 | `write_cost_s3.rs` | Bucket-gated (skips without `OMNIGRAPH_S3_TEST_BUCKET`) twin of `write_cost.rs` on the same `helpers::cost` harness: gates the **data-table opener** term (per-write latest-version resolution flat across commit depth on a real object store — per-version GETs are invisible on local FS). A cost gate, not a correctness test — run on demand, not in the every-merge `rustfs_integration` job (see the backend-split note in "Cost-budget tests" below) |