refactor(8.0): graph analytics contract — intent names, not algorithm names

The public brain.graph.* surface and the GraphAccelerationProvider seam must name
operations by INTENT, not by the algorithm that happens to implement them — so a
plugin can swap algorithms without the contract lying. The JS fallback computes
communities via connected-components and rank via PageRank, but a native provider
(cor) is free to use Louvain/Leiden for communities and personalized-PageRank /
eigenvector-centrality for rank: same intent, different algorithm, same name.

Renamed the (not-yet-implemented) Phase-C analytics methods + their option/result
types on GraphAccelerationProvider:
- pageRank -> rank            (PageRankOptions -> RankOptions; dropped the
                               pagerank-internal damping/maxIterations/tolerance
                               knobs from the contract — each impl tunes itself)
- connectedComponents -> communities   (ComponentsOptions -> CommunitiesOptions,
                               mode:'weak'|'strong' -> directed?:boolean;
                               GraphComponents -> GraphCommunities, componentIds/
                               Count -> communityIds/Count)
- shortestPath -> path        (ShortestPathOptions -> PathOptions; weight -> by:'hops'|'weight')
- neighborhoodSample -> sample (NeighborhoodSampleOptions -> SampleOptions)
- topByDegree -> mostConnected (TopByDegreeOptions -> MostConnectedOptions)

traverse / edgesForNode / graphCursorOpen/Next/Close + GraphScores/GraphPath/
OpaqueIdSet/Subgraph are UNCHANGED — everything cor has already built is untouched;
this is a pure pre-implementation rename (cor coordinated). JSDoc reworded to state
the algorithm is the provider's choice. index.ts exports + the native-seam test
mock updated. tsc/unit 1517/integration 599 green.

tests/unit/brainy/graph-native-routing.test.ts

@@ -45,11 +45,11 @@ function makeMockAccel() {
     graphCursorClose: async () => {
       calls.cursorClose++
     },
-    pageRank: async () => empty,
-    connectedComponents: async () => ({ nodeInts: new BigInt64Array(0), componentIds: new Uint32Array(0), componentCount: 0 }),
-    shortestPath: async () => null,
-    neighborhoodSample: async () => state.traverseResult,
-    topByDegree: async () => empty
+    rank: async () => empty,
+    communities: async () => ({ nodeInts: new BigInt64Array(0), communityIds: new Uint32Array(0), communityCount: 0 }),
+    path: async () => null,
+    sample: async () => state.traverseResult,
+    mostConnected: async () => empty
   }
   return { provider, state }
 }