docs: record the a11y tail, and four names written where nothing reads

Phase 3 shipped in six landings and a11y.md is closed, which closes all
four audits from 2026-08-11.

The pass's one lesson is that an accessible name is computed on the
element carrying the role, and every tier we check with looks somewhere
else: the audit read the source and credited a name that was never
computed, an AX sweep read the tree and reported a placeholder-only box
as clean, and a component test asserted the attribute and pinned the
bug it existed to prevent.

Six of the audit's claims turned out to be wrong or smaller than
written, and one of the plan's own findings was false — the page
header's sort control is named on all nine views. All of them are
written down, which is where a third of the value of the last two plans
came from.

.pi/skills/yellowjacket-dev/SKILL.md

@@ -18,7 +18,7 @@ here has disappeared.
 
 ## Read this part before you fail
 
-Fourteen things cost a cycle each the first time. They are here, not in a
+Fifteen things cost a cycle each the first time. They are here, not in a
 reference, because you need them *before* the failure, not after.
 
 - **Time out every binding call.** A bound Go method called with wrong
@@ -54,6 +54,16 @@ reference, because you need them *before* the failure, not after.
   `label` to `aria-labelledby` — so a new dialog that forgets to call
   the helper from `updated()` is invisible to
   `getByRole('dialog', {name})`.
+- **A name is computed on the element carrying the *role*, and Web
+  Awesome puts the role in its own shadow root.** `aria-label` on a
+  `<wa-slider>` or a `<wa-dialog>` host never reaches the tree. Use the
+  component's own `label` (plus `styles/wa-slider-label.css.ts`, since
+  a slider's is visible) or `utils/name-dialog.ts`. And in the light
+  DOM, a `<label>` that is a *sibling* of its control with no `for`
+  names nothing — that was 24 of the 93 controls on Settings.
+  **`getFullAXTree` is how you check, and "0 unnamed" is not the whole
+  answer**: a `placeholder` is an accname fallback, so a box labelled
+  only by one reports clean.
 - **The a11y snapshot cannot check an accessible name on a dialog.**
   `playwright-cli snapshot` prints `- dialog [ref=…]` with no name
   whether the dialog is named by `aria-labelledby`, by `aria-label`,
@@ -66,7 +76,7 @@ reference, because you need them *before* the failure, not after.
   `--browser=webkit` is CI-only; local work is Chromium. CI runs it
   with `if: !cancelled()` so a chromium failure does not silently
   skip it, which it did for two sessions.
-- **CI's `e2e` job is green on both engines** (54 specs each) since the
+- **CI's `e2e` job is green on both engines** (88 specs each) since the
   container got an audio device that keeps time. If playback specs
   start failing there again, check the **`The sink plays at real time`**
   step first: ALSA's `null` plugin consumes 3000 ms of audio in 2.96 ms,
@@ -74,9 +84,9 @@ reference, because you need them *before* the failure, not after.
   reads as an app bug and cost two sessions of that suspicion.
 - **`make e2e` needs `SEED=default`.** Its specs assert on fixture
   content — unicode tracks, the fixture artists, a known playable file.
-  Run against the `bulk` seed a measurement session left behind and 13
-  of 36 fail, in a list that reads exactly like a regression in
-  whatever you are holding. `make dev-headless SEED=default` first.
+  Run against the `bulk` seed a measurement session left behind and a
+  third of them fail (13 of 36, when it was measured), in a list that
+  reads exactly like a regression in whatever you are holding. `make dev-headless SEED=default` first.
 - **…and the suite spends state it cannot always give back.**
   `view-lifecycle.spec.ts` **skips an autotag album** on every run, out
   of the eleven the seed has, and does not put it back — so around the
@@ -180,7 +190,7 @@ and a CI step over every commit in a push) rejects a subject that is not
 `--no-verify` commit skips it locally and meets it in CI.
 
 Two things about the e2e tier that are not obvious until they bite.
-**The 36 specs share one backend process in file order**, so a spec
+**The 88 specs share one backend process in file order**, so a spec
 that leaves the app somewhere passes alone and fails the suite — leave
 the UI as you found it, and *wait* for it rather than trusting the
 click to have finished. The queue panel's width is animated and the