fix(driver-modbus-addressing): resolve Low code-review findings (Driver.Modbus.Addressing-006,007,009)

- Driver.Modbus.Addressing-006: broaden the catch in TryParseFamilyNative
  so a future helper throwing a non-Argument/Overflow type still satisfies
  the try-parse contract.
- Driver.Modbus.Addressing-007: document that the address grammar does
  not carry ModbusStringByteOrder (the structured-tag path does);
  add a 'Grammar scope' bullet to docs/v2/dl205.md.
- Driver.Modbus.Addressing-009: reword the ModbusModiconAddress comments
  so they don't imply a leading-digit invariant the parser doesn't
  enforce.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/v2/dl205.md

@@ -43,6 +43,15 @@ that a naive Modbus client will byte-swap [1][2].
   really "read 10 consecutive holding registers starting at the Modbus address
   that V2000 translates to (see next section), unpack each register low-byte
   then high-byte, stop at the first `0x00`."
+- **Grammar scope** (Driver.Modbus.Addressing-007): the
+  `ModbusStringByteOrder` knob (HighByteFirst / LowByteFirst) is **not**
+  expressible through the `ModbusAddressParser` grammar string — the 3rd grammar
+  field is the multi-register word/byte order (ABCD/CDAB/BADC/DCBA) and the 4th
+  is the array count, so there is no token slot for the per-string byte order.
+  Tags that need low-byte-first packing on DL205 must set
+  `ModbusTagDefinition.StringByteOrder = LowByteFirst` via the structured tag
+  form (the driver config DTO). The grammar default produces high-byte-first
+  strings (matches Ignition / Kepware default behaviour).
 
 Test names:
 `DL205_String_low_byte_first_within_register`,