Stop a delegate deferring somebody else's medication reminders

Found by an adversarial pass over the release candidate before it was tagged,
and it is the reason the tag waited.

`POST /api/medications/intake` is admitted for delegates because a caregiver
standing next to the patient has to be able to say the tablet went down. It is
an update, though, and the same body can carry two other things. Snoozing
writes `snoozedUntil` on the OWNER's medication row, and the reminder cron
skips that medication for as long as the stamp is in the future. The field
takes any future instant. So somebody with write access could stop another
person's medication reminders for years, and three things made it quiet: the
owner is deliberately not notified of a delegated snooze, the activity feed
renders the whole family as "marked a dose", and the only accurate trace was a
line in the admin audit log.

The second was flipping a dose the owner had already recorded — taken to
skipped and back, which rewrites their compliance history and refunds
inventory. The consent screen promises that changing what is already there
stays with the owner.

Both refuse for a delegate now and stay open to the owner, who is the only
person either was ever for. A refused attempt is filed under the owner and gets
its own sentence in the activity panel rather than borrowing the one for
marking a dose, because folding them together is what made the gap dangerous.

Two more from the same pass:

The consent notice named allergies among the things a delegate may add. That
left the admitted set before this release shipped, and it said so in six
languages on the one screen where somebody decides who may write into their
health record. It also omitted half of what IS admitted. The copy now matches
the frozen list, and the test asserts the withdrawal rather than only the
presence of the rest.

The banner told a WRITE delegate nothing at all — the mode line rendered only
in the read case, guarded by a comment stating that write grants did not exist
yet. This is the release that made them exist. It matters that the banner say
it, because the rule that a refused control is absent rather than disabled
rests on the banner naming the mode globally.

And a third instance of the substitution this release already fixed twice: the
BMI chart divided the owner's weights by the height of whoever was looking.
Inside a shared record it draws nothing now rather than a number belonging to
two different people.

src/app/api/medications/intake/route.ts

@@ -283,6 +283,61 @@ export const POST = apiHandler(async (request: NextRequest) => {
     return apiError("Intake event not found", 404);
   }
 
+  // v1.36.1 — this route is admitted for delegates because marking a dose is
+  // the thing a person standing next to the patient needs to do. It is an
+  // UPDATE, though, and two of the transitions it can express are not that.
+  //
+  // Snoozing writes `snoozedUntil` on the OWNER's medication row, and the
+  // reminder cron skips a medication for as long as that stamp is in the
+  // future. The field is unbounded, the owner is deliberately not notified of
+  // a delegated snooze (there is nothing useful to say about a thirty-minute
+  // deferral), and the activity feed renders the whole family as "marked a
+  // dose". So a delegate could switch the owner's medication reminders off for
+  // years, and every surface that exists to make delegation visible would
+  // describe it as marking a dose. In an adherence product that is the worst
+  // thing on this route.
+  //
+  // Flipping an already-resolved event is the other one: taken to skipped and
+  // back rewrites the owner's compliance history and refunds inventory. The
+  // shipped promise, on the consent screen and in the release notes, is that
+  // editing what is already there stays with the owner. Marking a dose that is
+  // still open is a contribution; changing a decision the owner already
+  // recorded is an edit.
+  //
+  // Both refuse for a delegate and stay open to the owner, who is the only
+  // person the snooze and the correction were ever for.
+  if (actor.id !== user.id) {
+    const alreadyResolved = existing.takenAt !== null || existing.skipped;
+    const refusal =
+      status === "snoozed"
+        ? "snooze"
+        : alreadyResolved
+          ? "resolved_event"
+          : null;
+    if (refusal) {
+      annotate({
+        action: { name: "medications.intake.update.refused" },
+        meta: { reason: refusal },
+      });
+      // Filed under the OWNER. `auditLog` stamps the actor itself from the
+      // request's acting context, which is what puts this on the trail the
+      // owner's activity panel reads — a refused attempt to change their
+      // record is worth as much to them as a successful one.
+      await auditLog("medications.intake.update.refused", {
+        userId: user.id,
+        ipAddress: getClientIp(request),
+        details: { intakeId, status, reason: refusal },
+      });
+      return apiError(
+        refusal === "snooze"
+          ? "Snoozing a reminder is not part of shared access"
+          : "Changing a dose that is already recorded is not part of shared access",
+        403,
+        { errorCode: "sharing.not_permitted" },
+      );
+    }
+  }
+
   // v1.8.5 — resolve + server-validate the optional injection site for a
   // "taken" toggle. A site outside the medication's effective allowed
   // set is a hard 422; non-injection / tracking-off / non-taken drops it.
@@ -557,9 +612,8 @@ export const POST = apiHandler(async (request: NextRequest) => {
   }
 
   // v1.36.x — "somebody else marked your dose". The helper refuses on self and
-  // on a snooze, resolves both names itself, and never throws; awaited because
-  // the latency it adds lands on the caregiver's request and never on the
-  // owner's own hot path.
+  // on a snooze, resolves both names itself, and never throws.
+  //
   // Fire and forget, like every neighbour above. The dispatcher awaits each
   // channel in the cascade, so an unreachable one would have added its whole
   // timeout to the caregiver's request — the person standing next to the