fix: order a citation run ascending, and name each page once (#24)

docs/superpowers/specs/2026-10-07-source-citations-design.md

@@ -57,11 +57,14 @@ would have been asked are recorded here instead.
   answer cites nothing while sources exist, the list shows all of them, because
   then it is the only evidence of what was consulted. Rejected alternatives are
   in "Approaches considered".
-- **A2. Numbers are never renumbered.** Contiguous numbering from 1 in citation
-  order is the academic convention, but it would make the transcript disagree
-  with the model's own reasoning text and with the tool output a curious reader
-  can inspect. Keeping the model's numbers means one number means one thing
-  everywhere in the turn.
+- **A2. Numbers are never renumbered, though a run is ordered ascending.** Contiguous
+  numbering from 1 in citation order is the academic convention, but renumbering the
+  whole answer would make the transcript disagree with the model's own reasoning text
+  and with the tool output a curious reader can inspect. Order inside a single run is
+  normalised instead, because a model lists sources by rank rather than by number, so
+  `[2][1]` reads as "two, one" once the digits sit next to each other. `[3]` therefore
+  still means the third source the turn found, whether or not the answer cited the two
+  before it.
 - **A3. The list is answer content, not a tool log.** It is shown whether or not
   the Show Tool Calls preference is on. Hiding tool calls is about the activity
   line; a citation list is part of the answer's credibility.