feat(devx): accept a dotted member path in ADR-0087 type-surface-only references (#15724)

A `type-surface-only` reference was a bare identifier resolved to the FIRST
same-named definition in the file. On `packages/client/src/index.ts` that is not
a symbol identity: the file declares `get` 14 times and `delete` 10 times, so the
members two PRs actually narrowed had no addressable spelling at all, and the gate
answered a true sentence about a member the diff never touched. One card's whole
category was closed by the reference grammar rather than by a judgement about the
claim.

The grammar now also accepts a dotted member path, and the READER was widened in
the same commit: a dotted reference is resolved STRUCTURALLY through the
object-literal nesting it names, walked from the top of the file over the shared
comment- and literal-masked projection with offsets preserved, and the member's
definition is taken from inside the resolved body. Zero candidates, or more than
one, is reported by name and refused -- never guessed at. A line number is never
the disambiguator; this file's line numbers were measured to rot within one day.

Bare identifiers keep their exact previous behaviour, including the first-same-name
reading, which is what every marker written before this means. `runtime-interface-only`
refuses a dotted path by name: it reads a top-level type declaration, which has no
nesting to walk.

ADR-0087's marker grammar and this gate's accepted grammar are pinned to each other,
so both example blocks and the predicate-4 prose move in the same commit.


Claude-Session: https://claude.ai/code/session_012zGPuVVX3deAx9LdjK8jCk

Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]

docs/adr/0087-metadata-protocol-upgrade-contract.md

@@ -585,6 +585,7 @@ gate's log and its `--list` output.
 <!-- adr-0087: not-required (no-migration-prescription) <why> -->
 <!-- adr-0087: not-required (runtime-interface-only <path>#<Symbol>[, ...]) <why> -->
 <!-- adr-0087: not-required (type-surface-only <path>#<Symbol>[, ...]) <why> -->
+<!-- adr-0087: not-required (type-surface-only <path>#<a>.<b>.<member>[, ...]) <why> -->
 ```
 
 **The vocabulary is closed, and every exemption is re-verified on every run** — an
@@ -676,6 +677,7 @@ The vocabulary above gained a sixth answer:
 
 ```text
 <!-- adr-0087: not-required (type-surface-only <path>#<Symbol>[, ...]) <why> -->
+<!-- adr-0087: not-required (type-surface-only <path>#<a>.<b>.<member>[, ...]) <why> -->
 ```
 
 ### The dead end it closes
@@ -748,6 +750,23 @@ checks all four by name (`published`, `no-spec-diff`, `no-metadata-surface-diff`
    *both* revs and requires `any` / `unknown` / no annotation at base, and a
    concrete type at HEAD.
 
+   ⭐ **The reference is a bare symbol OR a dotted member path.** `<path>#<Symbol>`
+   resolves a bare name to the **first same-named definition in the file**, and on a
+   real SDK module that is not a symbol identity: `packages/client/src/index.ts`
+   declares `get` 14 times and `delete` 10 times, so the members PR #15445 and PR
+   #15451 actually narrowed had **no addressable spelling at all** — the category
+   was closed to them by the grammar rather than by any judgement about the claim,
+   and the gate answered a true sentence about a member the diff never touched
+   (#15627). A reference may therefore also be written `<path>#<a>.<b>.<member>`:
+   the object-literal nesting the member sits in, walked **structurally** from the
+   top of the file over a comment- and literal-masked projection, with the member's
+   definition taken from inside the resolved body. Bare references keep their exact
+   previous meaning. ⛔ A line number is never the disambiguator — this file's line
+   numbers were measured to rot within one day. A dotted path that resolves to
+   **zero** candidates, or to **more than one**, is reported by name and refused,
+   never guessed at: a reference that silently landed on the wrong same-named member
+   would be writable but wrong, which is worse than the refusal it replaces.
+
 ### ⭐ Predicate 4 is what makes this a narrowing rather than a hole
 
 This is the **only** category exempt from the `no-migration-prescription` refusal.