docs(wire-formats): correct XML codec fall-through description

[ottobolyos]

Summary

Replace the stale claim that v2.6/v2.7 XML namespaces fall through to the v2.5 reader path with a description matching the current dispatch behavior.

Root cause

docs/wire-formats/xml.md described the codec's fallback for unrecognized namespaces as reading against the v2.5 path. That was accurate against the old dispatch chain, which defaulted to new Version() on an unmatched namespace. It no longer matches the code.

Fix

Before:

For v2.6 and v2.7 namespaces, the codec falls through to the v2.5 reader path; the library's compliance posture for those versions is tracked under Compliance.

After:

For any namespace not enumerated above — including future spec versions the library has not yet been rebuilt against — the codec defaults to the latest supported version (MTConnectVersions.Max) rather than to an older reader path. This preserves forward compatibility: an incoming document declaring a namespace one minor version ahead of the library's compiled surface is still read against the newest known reader. The library's compliance posture for v2.6 and v2.7 is tracked under Compliance.

Dime review cycle 1

Retroactive backfill (2026-08-20). The initial 6-agent Ultrareview cycle exercised the docs-only fall-through fix inline against #229's code fix. Ledger reconstruction from commit history:

• [DOCS] documentation-audit — line 86 fall-through description patched to match the MTConnectVersions.Max fallback landed by fix(xml): dispatch v2.6/v2.7 namespaces + default unknown to Max #229; closed atomically in docs(wire-formats): correct XML codec fall-through description (38b99ac).
• [FINDING] code-review — verified against fix(xml): dispatch v2.6/v2.7 namespaces + default unknown to Max #229's code fix: fallback returns MTConnectVersions.Max (currently v2.7) for unrecognized namespaces, matching the new docs description.
• [FINDING:A08] security-audit — no security surface touched (docs-only change).
• [SIMPLIFY] simplification — no additional minimum-shape proposals surfaced.
• [IMPROVE] improvement — no impact-ranked follow-ups surfaced.
• [TEST] test-coverage-audit — no test surface touched (docs-only change); the dispatch-chain behavior is pin-tested by fix(xml): dispatch v2.6/v2.7 namespaces + default unknown to Max #229's [TEST] findings.

Dime review cycle 2

Retroactive backfill (2026-08-20). Second cycle re-opened after #229's Ultrareview surfaced F-DOC-002 + F-DOC-003 tracking three additional stale sites in the same file. Ledger:

• [DOCS] documentation-audit F-DOC-002/F-DOC-003 — three sibling stale sites surfaced by fix(xml): dispatch v2.6/v2.7 namespaces + default unknown to Max #229's cycle 1 review; extended patch atomically (bug-class-atomic rule) in docs(wire-formats): extend fall-through fix to cover v2.7 Max annotation... (38e8f20):
  • Line 3: "v1.0 through v2.5" → "v1.0 through v2.7"
  • Line 82: added v2.6 + v2.7 rows to the XSD-per-version table + moved Max annotation from v2.5 row to v2.7 row
  • Line 119: v1.9 caveat "returns the default empty Version" → "falls through to MTConnectVersions.Max (currently v2.7)"

(Zero unfixed findings — Ready-eligible.)

Depends on

• fix(xml): dispatch v2.6/v2.7 namespaces + default unknown to Max #229 — this doc catch-up only makes sense once the code fallback lands.