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.

.planning/NOTES.md

@@ -2028,3 +2028,104 @@ Six more things worth keeping:
   palette rewrite, twice, because the component tier has no `:root` and
   renders the fallbacks. The tier that *did* catch things was a unit
   test over the palette table and a probe against the running app.
+
+## A name lives where the role is, and neither the audit nor the sweep looks there
+
+Plan 008 phase 3: the tail of `a11y.md`, which closes it — and with it
+all four audits from 2026-08-11.
+
+The generalisation, and it is the whole of this pass: **an accessible
+name is computed on the element carrying the role, and every way we
+have of checking one looks somewhere else.** The audit read the
+*source* and credited a name that was never computed. My AX sweep read
+the *tree* and reported a weak name as no problem. A component test
+asserted the *attribute* and pinned the bug it was written to prevent.
+Three tiers, three different wrong answers, all about the same
+property.
+
+Concretely, and each of these is a finding:
+
+| where it was written | where the role is | computed name |
+|---|---|---|
+| `aria-label` on `<wa-slider>` | a div in its shadow root, `aria-labelledby="label"` | `""` |
+| `<label>` beside a `<select>` in `config-field` | the select | `""` |
+| `placeholder` on Explore's search input | the input | the placeholder |
+| `label` on `<wa-progress-bar>` | inner div's `aria-label` | correct |
+
+The first is `wa-dialog`'s trap one component over and cost two
+sessions in 007. The fix is different, though, and the difference is
+worth keeping: `wa-progress-bar`'s `label` *is* an `aria-label` and is
+invisible, so it is just the right API; `wa-slider`'s `label` is
+**visible**, so the name comes from the library's own property and
+`styles/wa-slider-label.css.ts` hides it by part. That is preferred
+over `name-dialog.ts`'s reach into the shadow root for one reason —
+if Web Awesome renames the part, the label becomes *visible* and
+correctly named, rather than silently nameless again. Choose the
+failure you would rather have.
+
+Nine more things worth keeping:
+
+- **A sweep for empty names cannot see a weak one.** A `placeholder`
+  is an accname fallback, so `getFullAXTree` reported the whole Explore
+  view *clean* — which is why `a11y.26` survived four phases of people
+  looking for exactly this class of bug. "0 unnamed" answers a
+  narrower question than it reads as, which is the third time in this
+  plan a *count* has done that.
+- **The count that sent Phase 1 hunting was wrong in both halves.**
+  "Two unnamed native `<select>`s, one of them the page header's sort
+  control on nine views": the sort control is named `Sort: ` by its
+  wrapping `<label>` (`from: relatedElement`) on all nine, and the two
+  unnamed roles were one `config-field` select and the *seek bar*.
+  Recorded as a finding in the plan, believed for a phase, false.
+- **…and the thing it was pointing at was nine times bigger.** With
+  Settings' sections expanded: **24 of 93 controls unnamed**, every
+  `config-field` select and toggle and all eighteen column checkboxes.
+  No finding names it, and `a11y.6` is not wrong — it says in its own
+  line that it scanned every `<button>`. Same shape as phase 2's
+  contrast number.
+- **A fix's own test can be pinning the bug.** `transport.test.ts`
+  asserted `aria-label` on the `wa-slider` host under the title
+  "carries an accessible name". It passed for six phases. *Run the
+  existing tests* found it — third plan running that this is the rule
+  that pays.
+- **`a11y.21`'s mechanism does not exist, and the real one is on the
+  other axis.** "The 4em bars grow while the viewport does not and
+  anything that no longer fits is clipped" — the middle grid row is
+  `1fr` and absorbs them exactly: at 200% text on 800×600 the bars go
+  64 → 128px, the panel 472 → 344px, and the footer still lands on 600.
+  Nothing is clipped vertically. Horizontally the shell is 784px inside
+  a 320px viewport (400% page zoom, the width 1.4.10 names) with 464px
+  of it behind `overflow: hidden`. Measure the axis the finding does
+  not mention.
+- **`overflow: hidden` still permits programmatic scrolling**, so
+  `scrollLeft = 9999` returns a healthy 464 on the build that has the
+  bug. My first spec passed against the broken build for that reason.
+  A wheel gesture is the probe. Fifth entry in this plan's "the probe
+  was wrong, not the code" column, and the tell was the oldest one
+  there is: **it could not fail.**
+- **A synthetic `MouseEvent` does not reach a delegated handler.**
+  Three probes in a row reported a queue row as never becoming active;
+  `getByTestId('queue-row').dblclick()` made it active immediately.
+  Delegation reads things a hand-built event does not carry.
+- **A finding can be half-closed by a phase that was not about it,
+  and the half that remains is smaller than the sentence.** `a11y.34`
+  reads "the sort direction is a 10px glyph *or nothing*" — Phase 1's
+  `aria-sort` closed the *or nothing*, leaving one declaration. Second
+  time in this plan (`a11y.11` was the first), and both times reading
+  the sentence rather than the residue would have built something that
+  already existed.
+- **The state a fix lands in, again, and it was three pixels.**
+  `a11y.29` takes the subtitle's bottom margin away with the `<h3>`,
+  which *shortens* the flex-centred title block and moves it **down**
+  into the bar's clip — the hgroup had measured 67px inside a 64px bar
+  since before any of this, and the descenders of "meant to bee." were
+  cut. Found by reading a screenshot of the fix, which is the fifth
+  regression in three plans that only a PNG has caught.
+
+And one thing that went right and is worth copying: **the marker for
+`a11y.22` is a shape drawn in padding the row already had.** The track
+list's grid columns are computed from the host width, so anything in
+the flow moves every cell on the playing row and nothing else. A
+`::before` triangle in the 8px left padding costs no layout, and both
+tiers assert it is *absent* on the other rows — a marker that renders
+everywhere satisfies "the playing row has one" for free.