docs: help pages, probe reference and session docs updated for the three new features

- 08-trigger.txt: names all four condition shapes and the buffer search; fixes the first
  paragraph and 'How to reach it' to match what the panel actually contains (fix 3).
- 10-measurements.txt: adds a Statistics bullet — one observation per recompute, what
  resets the history, what does not (fix 3).
- probe-readings.md: re-quotes condition-probe lines with level2= and mode= fields;
  corrects leg-2 window geometry (0.2 s / 10 % pre, not 1.0 s / 50 %); moves the
  wide-window reason to legs 1 and 3; fixes the search-probe scheduling note
  (search_probe calls condition_probe directly; do not also set CONDITION_MS) (fix 6).
- verification.md: corrects shape-2 window geometry to match the code (fix 7).
- invariants-session-and-export.md, README.md: document the measure_stats session key —
  position, type, default false (fix 8).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/claude/verification.md

@@ -180,9 +180,10 @@ precedent, not an exception.
 - `UDPSCOPE_PROBE_CONDITION_MS` — arms a qualified trigger against the mock and reports the latched
   `t0`, the measured pulse or band width, and sample values for the window condition. Schedules its
   own arm and report stages. `UDPSCOPE_PROBE_CONDITION_SHAPE` picks the leg: `0` pulse width `<`
-  (the glitch, the default, needs `--glitch-at`/`--glitch-width`), `1` pulse width `>`, `2` window
-  (uses `sine` with a 1.0 s window and 50 % pre), `3` dropout (needs `--quiet-at`; also uses
-  `sine` with a 1.0 s window and 50 % pre).
+  (the glitch, the default, needs `--glitch-at`/`--glitch-width`), `1` pulse width `>` (uses a
+  1.0 s window and 50 % pre so the opening edge of a 0.2 s pulse is captured), `2` window
+  (uses `sine` with a 0.2 s window and 10 % pre), `3` dropout (needs `--quiet-at`; uses `sine`
+  with a 1.0 s window and 50 % pre so the last crossing before the outage is captured).
 - `UDPSCOPE_PROBE_STATS_MS` — reports every measurement's accumulator (`n`, mean, sd, lo, hi),
   pauses, reports again with `dn=` per measurement, then resets and reports a third time. Three
   phases: `phase=0`, `phase=1` (after pause) and `phase=2` (after Reset). Needs