feat(list): --rank-by-backlinks — rank artifacts by inbound-link count (REQ-128)

[avrabe]

Completes REQ-128. --orphans (already shipped) finds artifacts with no links — asserted-but-unanchored claims. This adds the complement: rank by inbound-link count (descending) to surface the most depended-upon artifacts, i.e. the highest-impact-if-changed hubs.

$ rivet list --rank-by-backlinks --type requirement
    58 in  REQ-004   requirement   approved   23 out  Validation engine
    40 in  REQ-014   requirement   approved    0 out  ASPICE SWE.4/5/6 test structure
    38 in  REQ-007   requirement   approved   16 out  CLI and serve pattern
    …

• Text: inbound-count column. JSON: an inbound_links field per artifact.
• Built on LinkGraph::backlinks_to; exact integer counts only (no semantic/relevance ranking, per REQ-128 acceptance); deterministic, ties break by id. Composes with --type / --filter.

Verification

• Integration test list_rank_by_backlinks_orders_descending: ordering is non-increasing and every entry carries inbound_links.
• list_orphans_is_subset still passes; clippy --all-targets + fmt clean; rivet validate PASS (190), rivet docs check PASS.

REQ-128 flipped to implemented (both halves now delivered).

Implements: REQ-128

🤖 Generated with Claude Code

[github-actions]

📐 Rivet artifact delta

Change	Count
Added	0
Removed	0
Modified	1
Downstream impacted (depth ≤ 5)	0

Graph

graph LR
  REQ_128["REQ-128"]:::modified
  classDef added fill:#d4edda,stroke:#28a745,color:#155724
  classDef removed fill:#f8d7da,stroke:#dc3545,color:#721c24
  classDef modified fill:#fff3cd,stroke:#ffc107,color:#856404
  classDef overflow fill:#e2e3e5,stroke:#6c757d,color:#495057,stroke-dasharray: 3 3

Loading

Modified

ID	Changes
REQ-128

📎 Full HTML dashboard attached as workflow artifact rivet-delta-pr-398 — download from the workflow run.

_{Posted by rivet-delta workflow. The graph shows only changed artifacts; open the HTML dashboard (above) for full context.}

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Rivet Criterion Benchmarks'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 3dcf8b2	Previous: 8891494	Ratio
link_graph_build/10000	35891270 ns/iter (± 2334645)	25284311 ns/iter (± 1141574)	1.42
validate/10000	18190485 ns/iter (± 1817093)	12996001 ns/iter (± 417453)	1.40
diff/10000	9662918 ns/iter (± 718674)	7771074 ns/iter (± 117800)	1.24

This comment was automatically generated by workflow using github-action-benchmark.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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