fix(ui): give edge-key sort an explicit compare function

SonarCloud S2871 (CRITICAL/HIGH reliability) flagged the bare `.sort()`
on the shape-hash edge-key strings in FlowMap — the default sort coerces
to UTF-16 code units, so it's not a reliable alphabetical sort. Add a
`localeCompare` comparator (mirrors the sibling `.sort(compareIds)` on
the ids line). The shape hash stays deterministic; no behaviour change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LDQVJrixs2nJoea67a8pEG

Author: aksOps

ui/src/components/map/FlowMap.tsx

@@ -169,7 +169,7 @@ function FlowMapInner({
   // radial layout). Metric-only polls reuse these via the data memo below.
   const shapeKey = useMemo(() => {
     const ids = nodes.map((n) => n.id).sort(compareIds)
-    const es = edgeRefs.map((e) => `${e.source}->${e.target}`).sort()
+    const es = edgeRefs.map((e) => `${e.source}->${e.target}`).sort((a, b) => a.localeCompare(b))
     return JSON.stringify({ ids, es })
   }, [nodes, edgeRefs])
   const positions = useMemo(() => {