feat(rust): establish Rust graph computing modernization framework (#355) - #359

‼️ GitHub Actions branch filters use glob syntax, but /^release-.*$/ is rejected as an invalid branch name/pattern (actionlint reports the leading /, ^, and trailing / as invalid); the exact-head Rust CI run 31351599715 ended in startup_failure, so formatting, clippy, tests, and release build never ran. Please use a valid glob such as release-* and rerun the workflow.

⚠️ The Apache header contains You me obtain a copy, which makes the exact-head check-license-header job fail on this file. Please correct the standard license text to You may obtain a copy and rerun the license check.

‼️ degree counts every edge whose source is in range, but the fill loop skips an out-of-range destination. For example, from_edges(2, &[(0, 99, 1.0)]) allocates one slot and leaves it as the default 0 -> 0 edge, so PageRank/SSSP consume a topology that was never supplied. Please validate both endpoints when counting and filling, and return an error from the C API for invalid vertices.

‼️ This Dijkstra loop accepts negative weights and has no negative-cycle detection. A graph containing 0 -> 1 = -1 and 1 -> 0 = -1 keeps lowering both distances and pushing new heap entries, so the exported SSSP call can run without termination and exhaust CPU/memory. Please reject negative/non-finite weights at the API boundary or use an algorithm that detects negative cycles.

⚠️ The new Rust library is not reachable from the advertised Vermeer path: NewRustKernelBridge hard-codes available: false, and ComputePageRank always executes the Go fallback. The Java bridge likewise computes in Java and only declares nativeGetVersion, which does not match Rust's computer_kernel_version export. Please implement and test the JNI/CGO bindings and native-path selection, or document this PR as fallback-only instead of presenting an active Rust integration.

‼️ The Go fallback counts an edge in outDegree when only src is valid, but the propagation loop later requires both endpoints to be valid. With numVertices=2 and an edge (0, 99), vertex 0 divides its rank by an edge that contributes nothing, so the fallback result loses mass and diverges from the Rust path. Please validate both endpoints before counting, or reject invalid edges with an error.

‼️ computer_graph_add_edge() still returns success after computer_graph_finalize() has populated builder.csr. Subsequent edges are appended to edges, but both compute functions keep reading the old CSR, so the C caller silently computes an obsolete graph. Please reject additions after finalization or invalidate/rebuild the CSR before allowing computation.

⚠️ An out-of-range source_vertex is passed to SsspKernel::compute(), which returns an all-INFINITY vector, and the FFI function still returns 0. This is indistinguishable from a valid graph whose vertices are all unreachable. Please validate the source at the C boundary and return a documented error code.

⚠️ NaN > epsilon is false, so assert_parity([f64::NAN], [0.0], epsilon) returns Ok(()); l1_distance() likewise returns Ok(NaN). A non-finite kernel result can therefore pass the differential fixture. Please reject non-finite inputs/differences and add NaN/Infinity regression cases.

⚠️ PageRankKernel::new() accepts non-finite or out-of-range parameters without validation. A NaN damping factor produces NaN ranks, and a NaN tolerance prevents convergence because every comparison is false; damping values outside [0, 1] also violate the probability contract. Please validate finite damping/tolerance at the API boundary and return an error for invalid input.

⚠️ The PageRank test uses only a symmetric three-cycle, whose expected vector is uniform even if edge propagation is broken or the topology is ignored. Please add an asymmetric graph with a dangling vertex and assert a fixed reference result so transition and dangling-node handling are actually exercised.

⚠️ This new Java test is not included by the module's unit-test execution: computer-test/pom.xml includes only **/UnitTestSuite.java, and UnitTestSuite does not reference RustKernelBridgeTest. The class can compile while its fallback regression never runs in CI. Please add it to the suite or configure an explicit Surefire include, then verify the test count.

⚠️ The added Go bridge test is not exercised by the repository CI workflow, which builds Vermeer but does not run go test. Please add at least go test ./apps/compute (and a native-path job when bindings exist) so fallback behavior is continuously verified.

‼️ std::ptr is unused in this file, while the new workflow runs cargo clippy --all-targets -- -D warnings. Once the workflow startup issue is fixed, this import will fail the quality gate. Please remove it and rerun Clippy.

⚠️ computer_kernel_version() returns a pointer into a thread-local CString; that pointer becomes invalid when the calling thread exits, and the header does not document the borrowed lifetime or provide a copy/free contract. A C caller that stores the pointer or passes it across threads can use freed memory. Please return process-lifetime static storage or expose an explicit copy API and document ownership.

‼️ The workflow containing this new test step is still unexecutable on the exact head: actionlint rejects the existing push branch filter /^release-.*$/ at line 23, and run 31675719210 finished startup_failure with no jobs. Please replace the filter with a GitHub Actions glob such as release-*, then rerun and require a successful Vermeer CI run so this added test actually executes.

⚠️ This fallback only rejects numVertices == 0; dampingFactor, tolerance (including NaN/Inf/negative/out-of-range) and invalid endpoints are otherwise accepted or ignored, while the Rust C-ABI returns -4/-1 for those inputs and the roadmap promises identical validation. Please validate and return errors consistently, or revise the contract, and add regression tests.

⚠️ This fallback has no validation for dampingFactor or tolerance; NaN or out-of-range values flow into arithmetic and can return NaN or invalid ranks, while the Rust C-ABI rejects them with -4 and the roadmap promises parity. Please validate finite damping in [0,1] and finite non-negative tolerance, define the error behavior, and add regression tests.

‼️ The loop terminates on the maximum single-vertex difference (max_diff < tolerance), but the roadmap declares an L1 error bound. With N vertices, this permits aggregate L1 error up to N*tolerance, so the advertised parity guarantee is not met. Please accumulate the L1 difference for convergence, or change the contract and tests to match.

⚠️ epsilon itself is never validated. With epsilon = NaN, diff > epsilon is false, so finite mismatched vectors can return Ok; this lets an invalid tolerance bypass the differential check. Please reject non-finite or negative epsilon before the loop and add a NaN regression case.

⚠️ This is labeled as the standard Karate Club fixture, but it contains only 35 directed edges, all sourced from vertices 0-3; vertices 4-33 have no outgoing edges. The current test only checks non-empty data, so benchmarks and parity inputs are materially truncated. Please add the complete dataset and assert edge count/key adjacency, or rename and document this as a reduced fixture.

⚠️ Despite the powerlaw name, this generator gives every vertex an out-degree of only avg_degree + (src % 5), i.e. 10-14 for the benchmark input, with no heavy tail. The benchmark therefore does not exercise power-law hotspots or memory behavior. Please generate a reproducible heavy-tailed distribution or rename the fixture to match its regular topology.