feat(sql): authored write block — Update/Insert/Upsert/Procedure + timestamp stamp; ODBC scope + login docs (lmxopcua#781)

Item 2: a tag's optional `write` block picks the statement the driver builds from its own
catalog-validated identifiers (no authored SQL; values always bound):
- Update (default, unchanged back-compat UPDATE ... WHERE key; 0 rows = BadNoData)
- Insert (key+value[+stamp]; append for a WideRow topByTimestamp tag)
- Upsert: SQL Server MERGE WITH (HOLDLOCK), PostgreSQL INSERT ... ON CONFLICT, MySQL
  ON DUPLICATE KEY UPDATE (1-or-2 rows), Oracle MERGE from DUAL
- Procedure: named stored procedure resolved against the routine catalog by the catalog gate
  (INFORMATION_SCHEMA.ROUTINES / ALL_PROCEDURES), value/key/timestamp params by name (MySQL positional)
- stampTimestamp sets the tag's timestamp column to the write time (UTC)
Odbc serves Update/Insert only (shared SqlWriteSupport table). Constraint failures map to
BadEntryExists (unique) / BadOutOfRange (other integrity, data exception); everything else,
permission denied included, stays BadCommunicationError. WriteIdempotent stays false.
The parser refuses malformed blocks (strict keys/enums/param charset); DraftValidator emits
blocking SqlWriteBlockInvalid / SqlWriteModeUnsupported from the driver's own parse; the AdminUI
editor surfaces the same message.

Items 1 + 4 (docs/drivers/Sql.md): ODBC stays the ANSI SQL:2008 profile (native providers for
SQL Server/MySQL, DB2 unsupported) with an ops note on driver manager + vendor driver on every
Odbc and AdminUI host; read-only drivers require a SELECT-only login, writable drivers a login
limited to their write targets.

Tests: SqlWriteModeTests (parse, every dialect's SQL, gate, status map, SQLite end-to-end),
DraftValidatorSqlWriteBlockTests, AdminUI round-trip; live SqlWriteModesLiveTests on SQL Server,
PostgreSQL, MySQL, Oracle (seeds gain write_targets + set_target) and an Odbc write leg.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

docs/plans/2026-07-15-sql-poll-driver-design.md

@@ -219,6 +219,12 @@ becomes an `IAddressSpaceBuilder.Variable(browseName, displayName, DriverAttribu
 
 ### 3.4 `IWritable` — verdict: NOT in v1
 
+> **Built since (2026-11-09).** #753 shipped the opt-in single-row UPDATE; lmxopcua#781 item 2 built the
+> `write` block — but as **driver-built statements** (`mode` Update / Insert / Upsert / Procedure +
+> `stampTimestamp`, procedure parameter names), not the authored `sql` text sketched below: every
+> identifier goes through the catalog gate and every value is bound. The shipped contract is
+> [`docs/drivers/Sql.md` → Writes](../drivers/Sql.md#writes-opt-in-753-781).
+
 **v1 does not implement `IWritable`.** Rationale in §1. The P4 opt-in design: a tag may carry a
 `write` block describing a **parameterized** statement (never string-concatenated):