V48 (spec-impl): Cross-link 50/72 in glossary and §12.1

Point FAMILIARIZATION glossary and promotion commit-body section
at the §2.8 50/72 message law.

Author: geraldarthurdavis

.docs/FAMILIARIZATION.md

@@ -1083,7 +1083,8 @@ Guide: `packages/agent-generics/TOOLS-IN-PTRR.md`.
 | **PROVEN** | Generated proof appendix / `.bitcode/vN-*` artifacts. |
 | **QA finding tag** | Fully-qualified `V48-GateN-F*` in code comments and QA ledger (never bare `F26-B`). |
 | **Spec family** | Hand-authored SPEC + DELTA + NOTES + PARITY (+ PROVEN) for a version. |
-| **`(spec-only)` / `(impl-only)` / `(spec-impl)`** | Only legal Spec/Impl commit/PR subject labels (abbreviated; never expanded `*-only` / `specification-implementation` forms; subject ≤72 chars). |
+| **`(spec-only)` / `(impl-only)` / `(spec-impl)`** | Only legal Spec/Impl commit/PR subject labels (abbreviated; never expanded forms). |
+| **50/72 law** | Commit message shape: subject soft ≤50; blank line before body; body lines hard ≤72 (SPECIFYING §2.8). |
 | **Source-bearing** | Implementation that proves a SPEC claim (listed in G3-14 / parity). |
 | **Version branch** | Long-lived draft line `version/v48` (not product source versioning). |
 

.specifications/BITCODE_SPECIFYING.md

@@ -1186,7 +1186,9 @@ If the hand-authored family still truthfully points at the prior canonical targe
 
 ## 12.1 Commit Message Body
 
-The canonical commit message body must be derivable from:
+Every commit message obeys the **50/72 law** in §2.8 (subject soft ≤50, blank
+line, body lines hard ≤72). In addition, a **canonical promotion** commit
+message body must be derivable from:
 - version,
 - proof-source commit,
 - delta accepted decisions,