feat(focas): real FANUC 30i/31i-B PDU-v3 support (live-validated on a 31i-B)

First real FOCAS hardware contact (Makino Pro 5 / 31i-B @ 10.201.31.5). A full
v3 data-PDU capture corrected the initial diagnosis: the v3 block envelope is
identical to v1, so only specific payload structs / request math / one client
robustness gap were wrong — not "framing rewrites".

Fixes (all re-validated live through the fixed driver):
- version gate: accept inbound PDU {1,3}, keep emitting v1 (FocasWireProtocol).
- cnc_rdtimer: 8-byte {minute,msec} payload is little-endian (ParseTimer) — the
  only decode with an in-range msec field.
- pmc_rdpmcrng: request range widened to the data-type byte width
  (end = start + width - 1) so a Word/Long isn't truncated to 0 values
  (was spurious BadOutOfRange); decode extracted to ParsePmcRange.
- cnc_rdsvmeter: per-axis LOADELM is 8 bytes (not 12) and names come from the
  0x0089 block — ParseServoMeters fixes the misaligned 655360 garbage. Also the
  "hang" was NetworkStream.ReadAsync not aborting a stalled socket: ReadExactlyAsync
  now disposes the stream on cancellation so a stalled peer can't wedge a poll loop.
- cnc_rddynamic2: contract guard rejecting axis < 1 (driver poll already 1-based).
- FocasDriverProbe: run a real wire session (initiate + cnc_statinfo) instead of
  degrading to Ok=true "TCP reachability only" when FWLIB is absent — a bare TCP
  listener no longer reports HEALTHY.

cnc_rdparam (0x000e) is unsupported on this control — EW_FUNC across 14
request-framing variants x 4 known-present params; needs a reference FWLIB trace
or is restricted. Deferred (deployed config uses macros, not parameters).

Tests: FOCAS suite 234 green (+16), full solution builds 0 errors. Raw v3
captures checked in under tests/.../Fixtures/v3/. Capture tools under scripts/focas/.

Docs: docs/plans/2026-06-25-focas-pdu-v3-{30i-b-support,implementation-plan}.md,
docs/drivers/FOCAS.md, docs/v2/focas-version-matrix.md,
docs/deployments/wonder-app-vd03-makino-z-34184.md.

docs/drivers/FOCAS.md

@@ -15,6 +15,21 @@ OtOpcUa is **read-only** against FOCAS; all reads go over the native wire
 protocol using the documented command IDs. Writes return
 `BadNotWritable` by design.
 
+> **PDU version (v3 / FANUC 30i/31i).** The wire client **accepts inbound PDU versions `{1, 3}`**
+> (`FocasWireProtocol`) while still emitting v1 on requests. Older controls + the docker mock answer
+> v1; modern controls (Makino Pro 5 / FANUC **31i-B**) answer v3. **Validated live against a real
+> 31i-B (`10.201.31.5`) 2026-06-25:** sysinfo, axis/spindle names, dynamic positions/feed/spindle,
+> program/mode, **macros**, **timers** (8-byte payload is little-endian {minute, msec}), **PMC range**
+> (request widened to the data-type byte width), **servo meters** (8-byte LOADELM stride + names from
+> the 0x0089 block; load *scaling* still to be confirmed at commissioning), and **alarms** all read
+> correctly. The driver `cnc_rddynamic2` poll is 1-based. **`cnc_rdparam` is unsupported on this
+> control** — every request-framing variant returns `EW_FUNC` (likely a wrong v3 command id; needs a
+> reference FWLIB trace). The Test-Connect probe now runs a real wire session (initiate + cnc_statinfo)
+> instead of a bare TCP check. Full finding, captured wire bytes, validation results, and analysis:
+> [`docs/plans/2026-06-25-focas-pdu-v3-30i-b-support.md`](../plans/2026-06-25-focas-pdu-v3-30i-b-support.md)
+> + [`…-implementation-plan.md`](../plans/2026-06-25-focas-pdu-v3-implementation-plan.md).
+> Capture tools: `scripts/focas/capture-initiate.py`, `scripts/focas/capture-v3.py`.
+
 ## Project split
 
 | Project | Target | Role |