Review 07 P7 (rest): adjacent words on one data file were never coalesced
(one round trip per tag) although the array path proves the transport can read
a span. Within a device pass, scalar tags on one N/B/F/L file within 8
elements of each other (block <= 200 data bytes, under the 236-byte typed-read
limit) now ride one multi-element read and are decoded from their offsets with
exactly the CLR types the single-tag path returns (int / float / bool).
Only shapes the single path decodes identically are coalesced: indirect,
sub-element, array, file-number-less (S:/I:/O:) and width-mismatched tags keep
the single path. A block the device refuses (an authored element past the end
of the file, a native PLC-5 non-N file) falls back to per-tag reads for its
members and its shape is remembered; a comms fault fails the members together.
New driver-config key coalesceReads (default true) with an AdminUI switch
(Razor change: AbLegacyDriverForm, for the Wave 4 live check). Adds an
env-gated ab_server parity case (coalesced == per-tag values).
Refs #738
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty
530f4bdcd4