Adds optional `@N` path suffix to FocasAddress (PARAM:1815@2, R100@3.0,
MACRO:500@2, DIAG:280@2/1) with PathId defaulting to 1 for back-compat.
Per-device PathCount is discovered via cnc_rdpathnum at first connect and
cached on DeviceState; reads with PathId>PathCount return BadOutOfRange.
The driver issues cnc_setpath before each non-default-path read and
tracks LastSetPath so repeat reads on the same path skip the wire call.
Closes#264
New FocasAreaKind.Diagnostic parsed from DIAG:nnn (whole-CNC) and
DIAG:nnn/axis (per-axis), validated against a per-series
FocasCapabilityMatrix.DiagnosticRange table (16i: 0-499; 0i-F family:
0-999; 30i/31i/32i: 0-1023; Power Motion i: 0-255; Unknown: permissive
per existing matrix convention).
IFocasClient gains ReadDiagnosticAsync(diagNumber, axisOrZero, type,
ct) with a default returning BadNotSupported so older transport
variants degrade gracefully. FwlibFocasClient implements it via a new
cnc_rddiag P/Invoke that reuses the IODBPSD struct (same shape as
cnc_rdparam). FocasDriver.ReadAsync dispatches Diagnostic addresses
through the new path; non-Diagnostic kinds keep the existing
ReadAsync route unchanged.
Tests: parser positives (DIAG:1031, DIAG:280/2, case-insensitive,
zero, axis-8) + negatives (malformed, axis>31), capability matrix
boundaries per series, driver-level dispatch verifying axis index
threads through, init-time rejection on out-of-range, and
BadNotSupported fallback when the wire client doesn't override the
default. 266/266 pass in Driver.FOCAS.Tests.
Closes#263
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
