feat(arrays): advertise AbCip/AbLegacy/TwinCAT array writes in DriverArrayWriteSupport

The Wave-2 lanes gave AbCip, AbLegacy and TwinCAT real whole-array write
encoders (review 07 U10/U9), but the capability table still listed all three
as scalar-only, so every array node materialised read-only and a client write
was BadNotWritable before it reached the driver.

Rows added, each listing only what WriteAsync encodes end to end:
- AbCip: SInt/USInt/Int/UInt/DInt/UDInt/Real/Dt/LInt/ULInt/LReal, declared
  length, not a safetyTag. BOOL/STRING/Structure arrays stay read-only.
- AbLegacy: Int/AnalogInt on N/B/A, Long on L, Float on F (file-width match),
  plain <file><n>:<word> address, <= 256 elements; not /bit, .sub, indirect,
  S:/I:/O:, nor native PLC-5.
- TwinCAT: every codec element type, declared length; not a BOOL bit-in-word
  path.
Elements convert in all three encoders, so the rows never key on an exact
node DataType (ScadaBridge int[] -> Int16 stays writable); they leave out
only node types whose elements never convert (DateTime/String over numeric,
Boolean on AbLegacy, STRING under DateTime on TwinCAT: culture-dependent).

Tests: driver-level parity for each driver (every element type x node type
plus shape cases, against the real write path), the AbLegacy parity tests
un-skipped, Core.Abstractions row tests, a composer test (three drivers
writable, refused shapes read-only), and the existing AbCip negative cases
moved to a BOOL array. Docs: Uns.md table, per-driver docs, data-plane rules.

Refs #737 #738 #739

Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT

docs/Uns.md

@@ -327,12 +327,23 @@ carried on the plan records (`RawTagPlan.ArrayWritable`, mirrored onto every UNS
 | **S7** | Yes | `Byte`/`Int16`/`UInt16`/`Int32`/`UInt32`/`Float32` (one contiguous block). Not `Bool` (would clobber neighbouring bits) nor the wide / String / DateTime types |
 | **OpcUaClient** | Yes | All — forwarded upstream unchanged; the upstream server decides (shape included) |
 | **Galaxy** | Yes | OPC UA `Boolean`/`Int32`/`Int64`/`Float`/`Double`/`String`/`DateTime` (the `MxValueEncoder` array variants) — **only with a declared `arrayLength`**: an undeclared length materialises an unbounded node, and a short whole-array write would *resize* the Galaxy attribute (mxaccessgw contract), so such a node stays read-only |
-| AB CIP, AB Legacy, TwinCAT, FOCAS, MQTT, MTConnect, Sql, Calculation | **No** — scalar-only write encoders; array nodes stay read-only and a client write is `BadNotWritable` | — |
+| **AB CIP** | Yes (#737) | `SInt`/`USInt`/`Int`/`UInt`/`DInt`/`UDInt`/`Real`/`Dt`/`LInt`/`ULInt`/`LReal` (`AbCipArrayCodec`, both transports). Not `Bool` (bit-packed DWORDs), `String` or `Structure`, nor a `safetyTag` |
+| **AB Legacy** | Yes (#738) | `Int`/`AnalogInt` on an N/B/A file, `Long` on an L file, `Float` on an F file — the encode width is the data file's, so a type that does not match its file stays read-only — on a plain `<file><number>:<word>` address, ≤ 256 elements. Not Bit / String / Timer / Counter / Control arrays, `/bit` or `.sub` addresses, indirect addresses, the `S:`/`I:`/`O:` files, nor any PLC-5 on the native transport |
+| **TwinCAT** | Yes (#739) | Every element type `TwinCATArrayCodec` lays out (numeric, `Bool`, `String`/`WString`, temporal); multi-dimensional PLC arrays are written row-major from the flat value. Not a BOOL bit-in-word path (`MAIN.Word.3`) |
+| FOCAS, MQTT, MTConnect, Sql, Calculation | **No** — scalar-only write encoders; array nodes stay read-only and a client write is `BadNotWritable` | — |
 
-Modbus, S7 and Galaxy additionally need a **declared length** — `isArray: true` *and* an integer
-`arrayLength >= 1`. The Modbus and S7 tag factories read anything else as a **scalar** tag (whose
-scalar encoder cannot take an array), even though the composer still materialises an array node;
-that node stays read-only.
+Every "Yes" driver but OpcUaClient additionally needs a **declared length** — `isArray: true` *and* an
+integer `arrayLength >= 1`. The tag factories read anything else as a **scalar** tag (whose scalar
+encoder cannot take an array), even though the composer still materialises an array node; that node
+stays read-only.
+
+**Elements convert; they are not exact-matched.** ScadaBridge writes CLR `int[]` / `List<int>` to Int16
+nodes: the node manager converts a numeric array to the node's element type, and the AB CIP, AB Legacy
+and TwinCAT encoders convert each element again to the controller's type (an element that does not fit
+is `BadOutOfRange`). Those rows therefore do not key on an exact node `DataType`; they leave out only
+node types whose elements never convert — a `DateTime` or `String` node over a numeric element, and a
+`Boolean` node on AB Legacy. An array tag deployed read-only before its driver gained an encoder turns
+writable on the next deploy (a surgical `ArrayWritable` update, no rebuild).
 
 Each "Yes" row is pinned against the driver's real encoder by a parity test in that driver's
 test project (`*ArrayWriteSupportParityTests`), so a driver gaining or losing an array encoder

docs/drivers/AbCip.md

@@ -252,7 +252,7 @@ The driver has two interchangeable wire transports, selected by one `DriverConfi
   write, read back, restored byte-exact). A user-approved **native array-element write** followed: `Program:EM01_PowerUnit._SEQ_EP[31]`
   0→4242→0 (the array's only alias targets `[1]`, no routine indexes or block-copies it; all 32 elements snapshotted
   twice before, after the write and after the restore — only `[31]` changed). Still ab_server-only: whole-array
-  writes (the driver has none), libplctag member writes, and fragmented writes. #566 is answered (the controller drops TCP; see "A target-closed CIP connection"). Mixed STRING/array/scalar
+  writes (#737; see [1-D array support](#1-d-array-support)), libplctag member writes, and fragmented writes. #566 is answered (the controller drops TCP; see "A target-closed CIP connection"). Mixed STRING/array/scalar
   Multiple Service Packet reads (#582) are proven on the press (one 5-read MSP, values equal to single reads). Results:
   [native-ab-transport-gate-results](../plans/2026-10-07-native-ab-transport-gate-results.md).
 - **libplctag cannot be deleted yet.** Scalar, UDT-member and STRING native writes are proven on a CompactLogix
@@ -262,7 +262,7 @@ The driver has two interchangeable wire transports, selected by one `DriverConfi
   libplctag member-write path is `ab_server`-only. See [Member writes](#member-writes).
 - ⚠️ RESIDUAL (#567): wide-struct **fragmented writes** (8-byte alignment) are unit-tested only. A write fragments only
   above `MaxRequestBytes` (4000 B on a Large Forward Open), so it needs a ~4 KB value; Z-35162 has no safe one (a DINT[32]
-  or a STRING is a single Write Tag, and AbCip has no whole-array write anyway). It stays open until a bench controller
+  or a STRING is a single Write Tag — and a whole DINT[32] array write, #737, is 128 B). It stays open until a bench controller
   or an approved large scratch tag exists.
 - Native browse (#572, resolved in code): listing paging no longer assumes ascending instance order, pages
   are paced, and a browse's template reads share one lease. Observed on Z-35162 (2026-10-09, 41
@@ -361,7 +361,17 @@ integration fixture is down during normal dev (Docker host fixture currently off
 
 **Live-verify** — integration-fixture-gated (requires `ab_server` Docker fixture on `10.100.0.35:44818`).
 
-**Deferrals** — array *writes*, multi-dimensional arrays, per-element historization.  Safety-partition array tags (`SafetyTag: true`) are excluded (GuardLogix write constraints extend to array writes).
+**Array writes (#737, review 07 U10)** — a whole-array write of exactly `arrayLength` elements, encoded by
+`AbCipArrayCodec` little-endian at the element width on both transports. Element values **convert**
+(ScadaBridge writes `int[]` to INT arrays); a value that does not fit is `BadOutOfRange`, one that cannot convert
+`BadTypeMismatch`, a different length `BadOutOfRange`, all before anything is sent. The controller buffer must be
+width × count (else `BadTypeMismatch`, checked before sending). Writable element types: `SInt`/`USInt`/`Int`/`UInt`/
+`DInt`/`UDInt`/`Real`/`Dt`/`LInt`/`ULInt`/`LReal`. **BOOL arrays** (bit-packed DWORDs), **STRING** and **structure**
+arrays are refused `BadNotSupported`, so their nodes stay read-only (`DriverArrayWriteSupport`); so does a
+safety-partition array tag (`safetyTag: true`, `BadNotWritable`). An array deployed read-only before #737 turns
+writable on the next deploy (a surgical `ArrayWritable` update). Proven on `ab_server` only until the hardware gate runs.
+
+**Deferrals** — multi-dimensional arrays, per-element historization, whole-array writes on hardware.
 
 See [Uns.md §Array tags](../Uns.md#array-tags-1-d) for the cross-driver coverage matrix
 and the UI authoring flow.
@@ -454,8 +464,9 @@ when it is browse-committed in `/raw`, and that tag writes like any other atomic
   `writable` key. The node is writable only once the operator sets the raw tag to `ReadWrite` (the
   node-manager gate); an authored `"writable": false` still refuses at the driver (`BadNotWritable`). The
   browse's `SecurityClass` (members inherit the parent symbol's read-only bit) is not consulted by the
-  commit. An element of a member array is authored by hand as `Seg.Points[2]`; a whole member array is
-  not writable (AbCip has no array encoder, `DriverArrayWriteSupport`).
+  commit. An element of a member array is authored by hand as `Seg.Points[2]`; a whole member array of an
+  atomic type is writable as an array tag (`isArray` + `arrayLength`, #737), a BOOL / STRING / structure member
+  array is not (`DriverArrayWriteSupport`).
 - **The request names the member.** One CIP symbolic segment per member (plus an element segment), the
   member's own CIP type, the member's own bytes — never the parent UDT, never a hidden host. Pinned at the
   request-byte level by `NativeAbCipTagRuntimeTests.A_member_path_write_names_the_member_and_sends_only_its_own_bytes`

docs/drivers/AbLegacy.md

@@ -304,8 +304,18 @@ N values of the declared `AbLegacyDataType`.  Maximum element count is 256 (PCCC
 limit).
 
 This closes the previously-noted limitation ("single-element addressing today") for the
-array read path.  The opt-in native transport also writes multi-element arrays (chunked); on libplctag
-array *writes* remain a follow-up.
+array read path.
+
+**Array writes (#738, review 07 U10 / r0 I3)** — on both transports, a whole-array write encodes exactly
+`arrayLength` elements at the **data file's** element width (N / B / A words, L longs, F floats). Element values
+**convert** (ScadaBridge writes `int[]` to Int16 nodes); a length mismatch or an element that overflows is
+`BadOutOfRange`, a non-numeric value `BadTypeMismatch`, before any runtime exists. Writable: `Int` / `AnalogInt` on
+an N / B / A file, `Long` on an L file, `Float` on an F file, on a plain `<file><number>:<word>` address of at most
+256 elements. These nodes stay **read-only** (`DriverArrayWriteSupport`): Bit arrays (bit-packed words), String /
+Timer / Counter / Control arrays (rejected at `FromTagConfig`), `/bit` and `.sub` addresses, a type that does not
+match its file (`BadTypeMismatch`), any PLC-5 on the native transport (writes refused before the wire), the
+`S:` / `I:` / `O:` files (libplctag refuses their translated names), and — deliberately — indirect addresses, whose
+element moves with the index word. An array deployed read-only before #738 turns writable on the next deploy.
 
 **Unit test coverage** — `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests/` covers
 the multi-element read path via the fake tag runtime.  The AB Legacy integration fixture is
@@ -313,8 +323,10 @@ down during normal dev.
 
 **Live-verify** — integration-fixture-gated (requires the AB Legacy Docker fixture).
 
-**Deferrals** — array *writes* on libplctag (the opt-in native transport writes them), multi-dimensional arrays, per-element historization.
-`arrayLength > 256` is rejected at init with an explicit error (PCCC payload cap).
+**Deferrals** — multi-dimensional arrays, per-element historization, array writes on hardware
+(`AbLegacyArrayWriteIntegrationTests` is green on `ab_server` and ready for a real controller via
+`AB_LEGACY_ARRAY_WRITE_BASE`).
+`arrayLength > 256` is clamped to 256 by the tag factory (PCCC payload cap), so such a node stays read-only.
 
 See [Uns.md §Array tags](../Uns.md#array-tags-1-d) for the cross-driver coverage matrix
 and the UI authoring flow.

docs/drivers/TwinCAT.md

@@ -362,6 +362,20 @@ element-typed CLR array (`bool[]`, `sbyte[]`, `byte[]`, `short[]`, `ushort[]`, `
   down (found live, below). A bit outside the parent's width, or a bit of a non-integer parent,
   is refused with `BadTypeMismatch`.
 
+### Array writes (#739, review 07 U9)
+
+An array node is **writable** (`DriverArrayWriteSupport`) for every element type the codec lays out —
+numeric, `Bool` (one byte per element, as TwinCAT stores a BOOL array), `STRING`/`WSTRING` and the temporal
+types. The write takes exactly `arrayLength` elements and **converts** each one (`ConvertForWrite`; ScadaBridge
+writes `int[]` to an Int16 node); a length mismatch or an out-of-range element is `BadOutOfRange` and a scalar
+value `BadTypeMismatch`, before any wire traffic. `WriteArrayAsync` then plans the layout from the resolved PLC
+array with the same `CheckArray` the read uses and encodes with `TwinCATArrayCodec.Encode` (the inverse of the
+decode); a shorter `arrayLength` writes the leading sub-range, and a multi-dimensional PLC array is written
+row-major from the flat 1-D value. A BOOL **bit-in-word** path (`MAIN.Word.3`) stays read-only as an array: it is a
+scalar bit write. Under a `DateTime` node only `DATE`/`DT`/`WSTRING` elements are writable, and under a `String`
+node only `STRING`/`WSTRING` (other conversions would depend on the text). An array deployed read-only before #739
+turns writable on the next deploy. Unit- and XAR-gate-tested; real-hardware proof is pending.
+
 ### Notification size cap
 
 ADS documents no notification size limit, and a live TwinCAT 2.11 target registered and