fix(copy): make delete confirmations, sleep-debt labels, and the glucose band honest

Three surfaces where the words no longer matched the code, plus the missing
web control for a preference the server already honours.

Delete confirmations. Four dialogs promised permanence on surfaces that
render an Undo: the measurements and mood bulk bodies, the lab-result body,
and the illness-episode body (which said "cannot be undone" sixty lines
below the code that fires the Undo toast). All four now use the same
sentence the single-row measurement and mood dialogs already used. A sweep
of every other confirmation in the tree found the rest accurate — the
biomarker cascade, the mood-tag purge, and the account purge keep their
warning because those deletes really are unrecoverable.

Sleep debt. v1.19.0 replaced the summed shortfall with a running balance
that credits catch-up sleep; the labels still described the old sum, so the
word contradicted the number for anyone who slept in after a short night.
Corrected in all six locales, plus the places the old semantics had
propagated: the Coach system prompt, the OpenAPI field descriptions the
native client reads, and four module docblocks.

Glucose reference band. `hasDiabetes` selects the tighter reference band and
grounds the Coach, but no web surface set it — a web-only account was pinned
to the non-diabetic scale with no way out. The control goes on Targets,
above the per-metric editor, because it answers the same question that page
answers and the two are ordered: it picks the default band, an override
below beats it. The copy says what it is — a reference band, not a
diagnosis, never inferred from a reading, no clinical action taken on it.

The passkey list was reported as always reading "never used". It does not
reproduce: the column is selected by the list route and stamped on every
verified assertion, both since v1.23.0. Pinned with tests on both halves so
the contract cannot quietly regress.

docs/api/openapi.yaml

@@ -2959,11 +2959,11 @@ paths:
         - Measurements
       summary: Sleep rhythm — sleep-debt + chronotype (v1.17.0)
       description: "Returns the two server-authoritative sleep-timing signals the Sleep page + iOS render off the same
-        canonical night reconstruction the Sleep Score uses: cumulative `sleepDebt` over the rolling window (calm
-        `partial` state under the night threshold) and MCTQ `chronotype` (MSF/MSFsc band + social jetlag, `learning`
-        state until enough free-day nights exist). Free vs work nights default to weekend = free in the user's timezone
-        (no work calendar). A read-only view over existing per-stage SLEEP_DURATION rows — no schema, no new measurement
-        type."
+        canonical night reconstruction the Sleep Score uses: the outstanding `sleepDebt` balance over the rolling window
+        (calm `partial` state under the night threshold) and MCTQ `chronotype` (MSF/MSFsc band + social jetlag,
+        `learning` state until enough free-day nights exist). Free vs work nights default to weekend = free in the
+        user's timezone (no work calendar). A read-only view over existing per-stage SLEEP_DURATION rows — no schema, no
+        new measurement type."
       responses:
         "200":
           description: Sleep-debt + chronotype DTO.
@@ -17930,12 +17930,13 @@ components:
                 - partial
                 - ready
               description: "`partial` until enough tracked nights exist (calm 'still learning'); `ready` once the rolling window can
-                assert a cumulative debt."
+                assert a balance."
             debtMinutes:
               type: integer
               minimum: 0
               maximum: 9007199254740991
-              description: Cumulative sleep debt over the window, in minutes, after caps.
+              description: Outstanding sleep-debt balance over the window, in minutes, after caps. A night below need adds its
+                shortfall; a night above need pays the balance down (floored at 0).
             needMinutes:
               type: integer
               minimum: 0
@@ -18076,9 +18077,9 @@ components:
         - chronotype
         - averagePerNight
       additionalProperties: false
-      description: "Server-authoritative sleep-rhythm read: cumulative sleep debt over the rolling window + MCTQ chronotype
-        (MSF/MSFsc band, social jetlag). Free vs work nights default to weekend = free in the user's timezone (no work
-        calendar). A view over existing per-stage SLEEP_DURATION rows — no schema, no new type."
+      description: "Server-authoritative sleep-rhythm read: the outstanding sleep-debt balance over the rolling window + MCTQ
+        chronotype (MSF/MSFsc band, social jetlag). Free vs work nights default to weekend = free in the user's timezone
+        (no work calendar). A view over existing per-stage SLEEP_DURATION rows — no schema, no new type."
     ListWorkoutsResponse:
       type: object
       properties: