Declare CB-WP-0016: the drop target that was never there, tier S

Provenance (tier S, one paragraph in lieu of survey and ADR): the human
check CB-EV-0012 kept stage 1 open on was run by the maintainer and
found the drag broken. Diagnosed against the live server first:
down=action-attack&up=seat-1 returns ok, so socket, guard, resolve and
dispatch are correct. seat-{n} ids exist only on the SVG circles in the
relationship graph; player_card emits the visible seat cards with no id,
so the target every action card names is inert. jsrun feeds element ids
straight in and never hit-tests, which is why every test passed.
Structural tier S: a defect fix inside an existing capability, and the
check it adds is a product test rather than a control gate. Chaos d4=3,
no override. Declaration 11 of 12.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

workplans/CB-WP-0016-the-drop-target.md

@@ -0,0 +1,136 @@
+---
+id: CB-WP-0016
+kind: product
+title: "The drop target that was never there"
+status: todo
+---
+
+# Purpose
+
+```
+structural tier  S   (a defect fix inside an existing capability — no new
+                      port, no canonical interface, no new dependency, and
+                      the check it adds is a product test, not a control
+                      gate)
+chaos            d4 = 3  → no override
+declared tier    S
+```
+
+Declaration 11 of 12. Tier S: one provenance paragraph in the commit
+message, no survey and no ADR. Steps 4–5 are not skipped.
+
+## Found by the human check, and by nothing else
+
+CB-EV-0012 §4 kept INTENT stage 1 open on one action the loop could not
+perform: run `cb-play --serve 0`, open the URL, confirm the table reads and
+a drag works. The maintainer ran it on 2026-08-02. **The table reads. The
+drag does not.**
+
+Diagnosed against the running server before any code was changed:
+
+```
+POST down=action-attack&up=seat-1   →  ok        (the game advanced)
+POST down=action-attack&up=action-attack →  "not a legal move here"
+```
+
+So the socket, the token guard, `resolve`, and command dispatch are all
+correct. The defect is in the emitted page.
+
+**`seat-{n}` ids exist only on the ~26 px circles inside the relationship
+graph** (`<g id="seat-0">`, `doc.rs:185`). The visible *seats* section
+cards are emitted by `player_card` as `<div class="card" data-viewer=…>`
+with **no id**. Every action card says *"drag Attack onto a seat, a
+problem, or the table"*, and the seat it points at is not a target.
+
+`#table`, `problem-{n}` and `freedom-{n}` are real targets, so the page is
+not wholly inert — the most natural target is.
+
+## Why every test in the repo passed
+
+`jsrun::gesture(html, down, up)` calls `__down(id)`, which synthesizes
+`{ target: { id: id } }`. **It feeds element ids straight in and never
+hit-tests.** So it establishes *"the script posts the ids it was given"*
+and never *"the page has an identified element where the instruction says
+to drop."*
+
+The 42-path coverage gate is blind for a related reason: it asserts each
+view field is **present in the parsed document**, which a `<div>` with no
+id satisfies perfectly.
+
+CB-WP-0015 closed a clause whose test was named for a property it did not
+check. This is the same shape one layer out — a harness answering a
+narrower question than its name implies — and it is the argument for
+having kept the human check as a blocker rather than closing stage 1 on
+green tests two passes ago.
+
+## Task: make the seat a drop target, and keep ids unique
+
+```task
+id: CB-WP-0016-T01
+status: todo
+priority: high
+```
+
+The seat card must carry the id `affordance()` already names for it.
+`seat-{n}` is currently taken by the SVG node, and duplicate ids are
+invalid HTML — so one of the two has to change, and **both must remain
+droppable.** The graph circle works today and someone will have learned it.
+
+Decide where the aliasing lives. Rust decides what a pointer fact means
+(ADR-0007 D5), so widening what `resolve` accepts is in bounds and
+inventing a new id vocabulary in the page is not.
+
+**Control:** dropping on the seat *card* and dropping on the graph *node*
+must produce the same command, and a test must go red if either stops
+resolving.
+
+## Task: a gesture that lands nowhere must say so
+
+```task
+id: CB-WP-0016-T02
+status: todo
+priority: high
+```
+
+`SCRIPT` currently does `if (!down || !up) { down = null; return; }` — no
+POST, no status line, nothing. That silence is why this defect survived a
+human sitting in front of it.
+
+The Rust side already holds the right principle: `resolve` refuses rather
+than substituting a default, because *"a drag that means nothing must mean
+nothing, not the first legal move."* Refusing is correct. Refusing
+**silently** is not.
+
+Make the outcome visible. Keep ADR-0007 control 5 intact — whatever the
+page reports must still be raw pointer facts with no game vocabulary, and
+the existing body-shape assertion must still hold.
+
+## Task: the check that closes the class
+
+```task
+id: CB-WP-0016-T03
+status: todo
+priority: high
+```
+
+**For every legal command, both ids `affordance()` produces must occur in
+the emitted document.** Pure Rust, no JS engine, no browser, deterministic.
+It fails on today's tree and it would have caught this the day the
+renderer was written.
+
+This is the deliverable that matters — T01 fixes one instance, this closes
+the class. An affordance naming an element that does not exist is exactly
+the harness-does-nothing shape, and it currently has no detector at all.
+
+Then `evidence/CB-EV-0014-*.md`:
+
+- **What the human check bought**, priced honestly against what it cost to
+  keep stage 1 open for two passes.
+- **Whether stage 1 closes now.** It needs the maintainer to drag again;
+  say so rather than closing it on a passing test, which is the failure
+  mode this whole pass is evidence for.
+- **Quote CB-WP-0015's final cost, not this pass's** — and note that
+  CB-EV-0013 §5 found the self-quoting rule fixes the wrong boundary, so
+  say plainly whether the figure has settled.
+- **Chaos: declaration 11 of 12.** The calibration window closes next
+  declaration.