Auto: ablegacy-9 — per-device timeout / retry overrides

Closes #252

docs/drivers/AbLegacy-Test-Fixture.md

@@ -123,6 +123,33 @@ cover the common ones but uncommon ones (`R` counters, `S` status files,
    network; parts are end-of-life but still available. PLC-5 +
    LogixPccc-mode behaviour + DF1 serial need specific controllers.
 
+## Per-device options (`AbLegacyDeviceOptions`)
+
+Each entry in `AbLegacyDriverOptions.Devices` carries:
+
+| Field | Type | Default | Notes |
+|---|---|---|---|
+| `HostAddress` | string | required | `ab://host[:port]/cip-path` |
+| `PlcFamily` | enum | `Slc500` | Slc500 / MicroLogix / Plc5 / LogixPccc |
+| `DeviceName` | string | null | Friendly label used in browse + diagnostics |
+| `Timeout` | TimeSpan? | null → driver-wide default | **PR 9 / #252** — wins over the driver-wide `Timeout`. Mix-and-match: SLC 5/01 ≈ 5 s, SLC 5/05 ≈ 2 s, MicroLogix 1100 ≈ 3 s |
+| `Retries` | int? | null → driver-wide default → 0 | **PR 9 / #252** — retries on transient `BadCommunicationError`; terminal errors surface on the first attempt |
+
+JSON shape (mirrored on `AbLegacyDeviceDto`):
+
+```json
+{
+  "HostAddress": "ab://192.168.1.10/1,0",
+  "PlcFamily": "Slc500",
+  "DeviceName": "slc-5-01-line-A",
+  "TimeoutMs": 5000,
+  "Retries": 1
+}
+```
+
+Per-device overrides also flow into the probe loop — slow chassis won't be
+falsely marked Stopped just because the driver-wide probe timeout is tight.
+
 ## Key fixture / config files
 
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/AbLegacyServerFixture.cs`