fix(abcip): final review I4 — a type mismatch is a refusal, not a comms fault

A native TypeMismatch (read status, write gate, or CIP 0xFF/0x2107) used
to evict the runtime and degrade health on every poll; for a sole lease
holder that meant Forward Close + Forward Open per poll, and an all-
mismatched driver tripped the comms-loss watchdog. It now reports
BadTypeMismatch, keeps the handle, leaves health alone and warns once per
tag per instance — reads, whole-UDT reads and writes, plus the libplctag
width check. Tests (red against the pre-fix driver): single create over N
polls, unchanged health, one warning, and one Forward Open / zero Forward
Close over the real native runtime against FakeCipTarget. AbLegacy has no
TypeMismatch path (its native runtime has no type check).

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

docs/drivers/AbCip.md

@@ -123,7 +123,8 @@ The driver has two interchangeable wire transports, selected by one `DriverConfi
   `Native`; libplctag remains available as the fallback.
 - ⚠️ **Client-visible:** native reports **`BadTypeMismatch`** for a mis-authored same-width type (for example a
   tag authored `DINT` where the controller holds a `REAL`), where libplctag returned Good garbage. Correct the
-  authored type; see [Native transport behaviour](#native-transport-behaviour).
+  authored type; see [Native transport behaviour](#native-transport-behaviour). It does not degrade driver
+  health or churn the connection; one Warning per tag names it.
 - **To fall back** one driver, set `"transport": "Libplctag"` in its driver config (or pick "libplctag
   (fallback)" in the AdminUI dropdown). To fall back a whole node, set `Drivers:AbCip:DefaultTransport` to
   `Libplctag` (below).
@@ -176,7 +177,10 @@ The driver has two interchangeable wire transports, selected by one `DriverConfi
   holds a `REAL` returns the REAL's bits as an integer with a Good status under libplctag, and
   `BadTypeMismatch` natively. That is the fix working, but a consumer will see Bad quality on tags that
   previously looked healthy: correct the authored type. Same-width signed/unsigned pairs are exempt, and
-  writes are gated on a mismatch too.
+  writes are gated on a mismatch too. A mismatch is a **deterministic configuration refusal**, handled like
+  an Unsupported refusal (final review I4): the tag's handle is kept (no re-create, no reconnect), driver
+  health is unchanged (no `Degraded`, nothing fed to the comms-loss watchdog), and the Warning is logged
+  **once per tag** per driver instance, not every poll. The same applies to the libplctag-path width check.
 - Malformed tag names put the device into backoff, as under libplctag (#570). STRING capacity includes the
   alignment pad (84, not 82) (#570).
 - **A refused operation is not a comms fault.** Any operation a runtime refuses as Unsupported (in AbCip, e.g.