docs: Stage 0 --- publish the per-step subclaim list before any grade

§3.3 of the arc framing requires the per-frontend table to grade each
cell as the MINIMUM over that step's required subclaims, and requires
the subclaim list to be published: a grade whose subclaims are unstated
is not falsifiable, which is the whole objection that section answers.

This commit is the list ALONE. No cell is graded yet, deliberately ---
the subclaims are the part a reader can disagree with by pointing at
something, and every grade inherits their errors. Grading in the same
commit would bury the reviewable half under the arguable one.

Two rules decide membership. Discoverability is a SUBCLAIM wherever it
is the step's substance --- steps 4, 7, 8 and 11 --- because "present
but nobody can find it" is the failure those steps exist to catch, and
the head-grade rule this replaces would have let it become annotation
text with no effect on closure. And anything load-bearing enough to name
as a defect is load-bearing enough to be a subclaim; an annotation
cannot absorb a failing one.

Performance, aesthetics and cross-editor parity are named as NOT
subclaims. Each is real and each is graded elsewhere or nowhere; folding
them in would make every cell a judgement about taste and the ordinal
would stop meaning anything.

Frontend-specific limitations are also excluded, because they are what
the three columns MEASURE --- encoding them in the subclaims would beg
the question the table exists to answer.

Step 12(c) is recorded as the worked example: a required subclaim
everywhere, structurally impossible on any daemon-backed frontend under
Q#DS9, so the GPU cell will fail it by CONSTRUCTION rather than by
omission. The old single-verdict table could not say that --- "Partial"
was doing the work of both "some of this is missing" and "some of this
cannot exist yet".

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai

COHERENCE.md

@@ -356,6 +356,52 @@ This journey should become a release gate. New architectural work should
 be evaluated partly by whether it improves, preserves, or complicates
 the journey.
 
+### 2a. Required subclaims per step (the GUI arc, Stage 0)
+
+**A grade whose subclaims are unstated is not falsifiable.** The
+per-frontend table below grades each (step, frontend) cell as the
+**minimum over that step's required subclaims** — never the first word
+of a prose verdict. This section is that list, published so a reader can
+disagree with a grade by pointing at a subclaim rather than at taste.
+
+Two rules decide what belongs here. **Discoverability is a subclaim
+wherever it is the step's substance**, not an annotation on it — steps
+4, 7, 8 and 11 are graded on whether a capability is *findable*, because
+"present but nobody can find it" is the failure those steps exist to
+catch. And **anything load-bearing enough to name as a defect is
+load-bearing enough to be a subclaim**: an annotation cannot absorb a
+failing one.
+
+| # | Step | Required subclaims |
+|---|---|---|
+| 1 | Install | (a) a documented install path completes on a clean machine; (b) the installed binary launches |
+| 2 | Launch unconfigured | (a) starts with no user config; (b) presents a usable editing surface; (c) raises no error the user must dismiss |
+| 3 | Open real project | (a) a file opens from the CLI; (b) a file opens from inside the editor; (c) a directory opens and is browsable; (d) the project root is established |
+| 4 | Understand interface | (a) the mode line reports buffer state; (b) a help surface exists; (c) **discoverable** — the route to it is advertised in-product, not only known |
+| 5 | Edit | (a) text edits apply and render; (b) undo/redo; (c) selection, kill and yank; (d) large and long-line files stay usable |
+| 6 | Language intelligence | (a) a server attaches for a supported language; (b) diagnostics surface; (c) completion, hover and go-to-definition are available; (d) styling reflects the server |
+| 7 | Find symbol / file | (a) open a file by path; (b) browse to a file without knowing its path; (c) find a symbol; (d) **discoverable** — the commands are bound or advertised |
+| 8 | Open terminal | (a) a terminal opens; (b) input and output round-trip; (c) it can be closed or killed; (d) **discoverable** — reachable by an advertised binding |
+| 9 | Build / test | (a) a build or test command runs; (b) its output is captured; (c) the output is navigable |
+| 10 | Inspect error | (a) errors are enumerated; (b) navigation reaches the site; (c) the site is marked in the buffer |
+| 11 | See background work | (a) work in flight is **visible without asking**; (b) a detailed view is reachable; (c) **discoverable** — reachable by an advertised binding; (d) cancellable |
+| 12 | Close + restore | (a) closing is clean and loses no data; (b) per-file state (cursor, scroll) restores; (c) the open-buffer set and window layout restore |
+
+**Deliberately NOT subclaims.** Performance, aesthetics, and parity with
+other editors: each is real, and each is graded elsewhere or nowhere.
+Folding them in here would make every cell a judgement about taste and
+the ordinal would stop meaning anything. **Frontend-specific
+limitations are also not subclaims** — they are what the three columns
+*measure*, so encoding them here would beg the question.
+
+**Step 12(c) is the worked example of why subclaims are per step and
+not per frontend.** It is a required subclaim everywhere, and Q#DS9
+makes it structurally impossible on any daemon-backed frontend — so the
+GPU cell fails it by construction rather than by omission. That is a
+finding the old single-verdict table could not express, because "Partial"
+was doing the work of both "some of this is missing" and "some of this
+cannot exist yet".
+
 ### Ground truth: the journey today
 
 **Grade: reaches step 5; thin from step 6 on.** Was **broken at step 3**