Commit 4 BINDING design specs into docs/proposals/mockups/ for durability

docs/README.md

@@ -239,3 +239,8 @@ system" + "Using it" + "Operating it" only).
   for the first one.
 - [`reports/`](reports/README.md) — the report-relay convention (see that
   directory's own README, which indexes every report currently merged).
+- [`proposals/mockups/`](proposals/mockups/README.md) — BINDING design
+  spec + companion static-HTML mockup bundles, one directory per round;
+  includes durability copies of specs recovered from session tmp storage
+  that committed code comments on open PR branches cite by filename (see
+  that directory's own README for why).

docs/proposals/mockups/README.md

@@ -0,0 +1,51 @@
+# docs/proposals/mockups/
+
+Design-artifact bundles: a BINDING owner-approved spec (`SPEC-*.md`) plus
+its companion static-HTML mockup, one directory per round. These are
+design artifacts, not application code — see each bundle's own header for
+its "how to view" instructions. Like the rest of `proposals/`, never
+published to the wiki (per
+[`../../documentation-process.md`](../../documentation-process.md)) — a
+spec here isn't necessarily shipped yet, and some (see below) are
+durability copies of work that landed only on an open PR branch, not
+`master`.
+
+- [`proposal-h/`](proposal-h/README.md) — mockups for
+  [`../proposal-h-display-layout-spec.md`](../proposal-h-display-layout-spec.md)
+  (the living `/display` spec) and its historical predecessor
+  [`../proposal-h-unified-display-page.md`](../proposal-h-unified-display-page.md).
+  See that directory's own `README.md` for the file-by-file breakdown.
+- [`rail-delegacy/SPEC-rail-delegacy.md`](rail-delegacy/SPEC-rail-delegacy.md)
+  — the `/editor` left rail delegacy round: the nine grey legacy
+  `AutofillCollapse` drop-downs removed, their contents folded into
+  designed elements. Companion mockup:
+  [`rail-delegacy-mockup.html`](rail-delegacy/rail-delegacy-mockup.html).
+- [`editor-polish/SPEC-editor-polish.md`](editor-polish/SPEC-editor-polish.md)
+  — the unified `/editor` consolidated polish round (eleven owner-settled
+  items + the slot-menu cue), inherited on top of the rail-delegacy round
+  above. Companion mockup:
+  [`editor-polish-mockup.html`](editor-polish/editor-polish-mockup.html).
+- [`cardback-pdfwait/SPEC-cardback-pdfwait.md`](cardback-pdfwait/SPEC-cardback-pdfwait.md)
+  — the `/editor` cardback flow (PKG 1) + PDF-generation wait experience
+  (PKG 2), inherited on top of both rounds above. Companion mockup:
+  [`cardback-pdfwait-mockup.html`](cardback-pdfwait/cardback-pdfwait-mockup.html).
+- [`wtc-rebuild/SPEC-wtc-rebuild.md`](wtc-rebuild/SPEC-wtc-rebuild.md) —
+  the "What's That Card?" (`/whatsthat`) rebuild spec: Tokyo-11 theme
+  adoption for the page's own prior bespoke identity. Companion mockup:
+  [`wtc-mockup.html`](wtc-rebuild/wtc-mockup.html).
+
+## Why these four are here (durability, not a new proposal)
+
+`rail-delegacy/`, `editor-polish/`, `cardback-pdfwait/`, and
+`wtc-rebuild/` were brought into the repo as verbatim durability copies
+(2026-07-24) of specs that previously lived only in a session's tmp
+directory — which does not survive past that session — while committed
+code comments on several open PR branches already cite each spec by
+filename as its binding authority. Same gap
+[`../../reference/funnel-spec.md`](../../reference/funnel-spec.md) closed
+when it was recovered during the 2026-07-23 D-lettering sweep (it had
+been cited from `docs/features/grid-selector.md` but never itself
+committed). Each file's own header names which committed comments cite
+it. These are reference copies of specs authored for their respective
+(still-open, not-yet-merged) PRs, not a statement that the surfaces they
+describe have shipped to `master`.