fix(discover): "in about a month" was unreachable in both clients — #2375

The days→months threshold (45) sat above the divisor (30), so a rounded
month count of 1 — which needs 15..44 days — could never be reached: every
one of those day counts hit the `in N days` branch first. The singular
branch was dead code on Android AND web.

Lowered the threshold to 30 in both clients, which makes 30..44 days read
"in about a month" instead of "in 44 days", and documented the invariant
(threshold must not exceed the divisor) next to each constant so the two
can't drift apart again.

Found by the unit test written for that branch, which is the whole reason
to assert on copy that looks obviously correct. Both suites now pin the
seam from both sides — 29 days and 30 days — so the branch can't go dead
again silently.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/models/Discover.kt

@@ -119,8 +119,15 @@ data class SuggestionSnoozeRef(
 
     private companion object {
         const val MILLIS_PER_DAY = 86_400_000.0
+
         // Below this, days read more naturally than a rounded month count.
-        const val DAYS_BEFORE_MONTHS = 45
+        //
+        // Must be <= DAYS_PER_MONTH, or the singular "in about a month" is
+        // unreachable: a rounded month count of 1 needs 15..44 days, and any
+        // threshold above 30 sends all of those down the days branch instead.
+        // This was 45 and the singular branch was dead code — the unit test
+        // for it is what surfaced that.
+        const val DAYS_BEFORE_MONTHS = 30
         const val DAYS_PER_MONTH = 30.0
     }
 }