review(Driver.Sql): findings + fix the missing default-schema fallback, the rowSelector doc, and a dead package ref

Driver.Sql-001 (Medium): SqlCatalogLoader.ReadDefaultSchemaAsync documented a
fallback to the sole visible schema when the server reports no default schema and
did not implement it, so a login with no DEFAULT_SCHEMA (or a Postgres search_path
that resolves to nothing) rejected EVERY unqualified authored table at the catalog
gate — a whole-driver BadNodeIdUnknown outage against a healthy database. Fixed;
SqlCatalogDefaultSchemaTests written red first, with a control proving the
ambiguous multi-schema case still refuses to guess.

Driver.Sql-003 (Medium): docs/drivers/Sql.md spelled the WideRow row selector at
the top level, but the parser reads those keys only inside a nested rowSelector —
a tag authored from the doc is refused and reads BadNodeIdUnknown (the #552 class,
via the documentation). Also removed the documented-but-nonexistent pollIntervalMs
per-tag field.

Driver.Sql-007 (Low): dropped the unused Microsoft.Data.SqlClient PackageReference
left behind by the .Dialect extraction (#526).

Open: 002 (no IN-list chunking vs the 2100/1000 provider bind caps), 004, 005, 006,
008, 009, 010.

docs/drivers/Sql.md

@@ -56,13 +56,18 @@ One row per tag. The driver matches `keyColumn = keyValue` and reads `valueColum
 The tag names its `columnName`; the row is picked either by a `whereColumn`/`whereValue` pair or by
 newest-timestamp.
 
+⚠️ **The selector keys live inside a nested `rowSelector` object**, not at the top level. A blob that
+spells `whereColumn` / `whereValue` / `topByTimestamp` beside `columnName` carries *no* row selector
+as far as `SqlEquipmentTagParser` is concerned: the tag is refused, the driver skips it, and it reads
+`BadNodeIdUnknown` forever. The typed editor, the browse-commit mapper and the deploy gate all use
+the nested form.
+
 ```json
 {
   "model": "WideRow",
   "table": "dbo.LineStatus",
   "columnName": "OvenTemp",
-  "whereColumn": "LineId",
-  "whereValue": "L1"
+  "rowSelector": { "whereColumn": "LineId", "whereValue": "L1" }
 }
 ```
 
@@ -71,10 +76,13 @@ newest-timestamp.
   "model": "WideRow",
   "table": "dbo.Readings",
   "columnName": "OvenTemp",
-  "topByTimestamp": "CapturedUtc"
+  "rowSelector": { "topByTimestamp": "CapturedUtc" }
 }
 ```
 
+`whereValue` may be authored as a JSON string, number or boolean (it is bound as a parameter either
+way). `keyValue` on the `KeyValue` model must be a **string**.
+
 ### `Query` — deferred to P3
 
 Named arbitrary-`SELECT`. **The v1 parser rejects it**, and that refusal is enforced end-to-end —
@@ -87,7 +95,11 @@ ignoring it later.
 |---|---|
 | `timestampColumn` | Source timestamp for the value. Absent ⇒ the driver stamps the poll time. |
 | `type` | Explicit OPC UA type override. Absent ⇒ inferred from the result set's column metadata. |
-| `pollIntervalMs` | Per-tag override of the instance's `defaultPollInterval`. |
+
+There is **no per-tag poll-interval field**. The interval is the subscriber's, floored by
+`PollGroupEngine.DefaultMinInterval`, falling back to the instance's `defaultPollInterval` when the
+subscriber names none. (A `pollIntervalMs` per-tag override was documented here for a while and never
+existed in the parser — nothing reads it.)
 
 ## Driver config