fix: remove duplicate methods introduced by phase5 merge (build fixes)

Two duplicate method definitions were introduced when feat/phase5-dashboard-redesign
was merged into main, because both the backend chain (PRs #12-16) and the phase5
branch independently added the same methods:

1. GraphStore.findEndpointNeighborsBatch(List<String>):
   - Kept: UNWIND/$ids/NodeKind.getValue() version (from backend chain, type-safe)
   - Removed: IN $nodeIds/string literal version (from phase5)

2. TopicLinkerTest.determinismTest():
   - Kept: multi-producer/multi-consumer test with PRODUCES+CONSUMES+PUBLISHES+LISTENS
     and TOPIC+EVENT nodes (more comprehensive, verifies target ID equality)
   - Removed: simpler 3-edge test (from backported detection-quality-fixes commit)

Fixes: javac compilation failures on main branch.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

Author: aksOps

src/test/java/io/github/randomcodespace/iq/analyzer/linker/TopicLinkerTest.java

@@ -376,30 +376,4 @@ void handlesMessageQueueNodeKind() {
         assertEquals(1, result.edges().size());
     }
 
-    @Test
-    void determinismTest() {
-        var topic = new CodeNode("topic:payments", NodeKind.TOPIC, "payments");
-        var prod1 = new CodeNode("svc:P1", NodeKind.CLASS, "P1");
-        var prod2 = new CodeNode("svc:P2", NodeKind.CLASS, "P2");
-        var cons = new CodeNode("svc:C1", NodeKind.CLASS, "C1");
-
-        var e1 = new CodeEdge();
-        e1.setId("e1"); e1.setKind(EdgeKind.PUBLISHES); e1.setSourceId("svc:P1"); e1.setTarget(topic);
-        var e2 = new CodeEdge();
-        e2.setId("e2"); e2.setKind(EdgeKind.SENDS_TO); e2.setSourceId("svc:P2"); e2.setTarget(topic);
-        var e3 = new CodeEdge();
-        e3.setId("e3"); e3.setKind(EdgeKind.LISTENS); e3.setSourceId("svc:C1"); e3.setTarget(topic);
-
-        List<CodeNode> nodeList = new ArrayList<>(List.of(topic, prod1, prod2, cons));
-        List<CodeEdge> edgeList = new ArrayList<>(List.of(e1, e2, e3));
-
-        LinkResult result1 = linker.link(nodeList, edgeList);
-        LinkResult result2 = linker.link(nodeList, edgeList);
-
-        assertEquals(result1.edges().size(), result2.edges().size());
-        for (int i = 0; i < result1.edges().size(); i++) {
-            assertEquals(result1.edges().get(i).getId(), result2.edges().get(i).getId());
-            assertEquals(result1.edges().get(i).getSourceId(), result2.edges().get(i).getSourceId());
-        }
-    }
 }