Docs: unlink report_20260830.log, which never travels

HANDOFF.md and HWTIMESTAMPING.md both linked report_20260830.log as if
it were in the repo. It is gitignored via *.log and stays on the
machine that produced it, so both rendered as dead links on GitHub.

Both files already said as much in their own prose — HANDOFF.md opens
by explaining it is self-contained precisely because the report does
not travel — so this only brings the markup in line with the text.

Demoted both to plain code spans noting they are local only, and
pointed HWTIMESTAMPING.md at HANDOFF.md and TIMEBASE.md for the numbers
that are actually inlined and do travel.

All internal markdown links across the repo now resolve.

Author: markwatson

HANDOFF.md

@@ -5,8 +5,8 @@ another machine. Self-contained: all key numbers are inline, because the
 `report_*.log` files are gitignored (`*.log`) and will NOT travel with the repo.
 
 Related: [HWTIMESTAMPING.md](HWTIMESTAMPING.md) (design sketch, conditional on
-the outcome below), [report_20260830.log](report_20260830.log) (full data,
-local only), [TESTING.md](TESTING.md) (how the chrony soak works).
+the outcome below), `report_20260830.log` (full data, local only — `*.log` is
+gitignored), [TESTING.md](TESTING.md) (how the chrony soak works).
 
 ---
 

HWTIMESTAMPING.md

@@ -11,7 +11,9 @@ genuinely unresolved and need investigation before anyone plans around them.
 > and the asymmetry trap below (fixing TX alone makes accuracy worse) still
 > applies in full.
 
-Measurement background is in [report_20260830.log](report_20260830.log).
+Measurement background was in `report_20260830.log`, which is **local only** —
+`*.log` is gitignored, so it did not travel with the repo. The numbers that
+matter are inlined in [HANDOFF.md](HANDOFF.md) and [TIMEBASE.md](TIMEBASE.md).
 
 ## Why bother