contract: unified ClassView render — facet value rows + is_a-walk resolution

[AdaWorldAPI]

Additive, zero-dep extension of lance-graph-contract::class_view implementing the operator-ratified unified ClassView render: any app calls the same projection — resolve (is_a rail) → carve (FieldMask) → emit — with routes as thin per-app skins. This closes the two gaps the q2 cockpit-server OSINT card surfaced in the contract.

What's added (all defaulted trait methods / new type — non-breaking for every implementor)

pub struct ValueRow<'a> { pub label: &'a str, pub predicate: &'a str, pub position: u8, pub value: u8 }

// on trait ClassView:
fn facet_rows<'a>(&'a self, class: ClassId, mask: FieldMask, facet: &[u8; 12]) -> Vec<ValueRow<'a>>;
fn is_a_parent(&self, _class: ClassId) -> Option<ClassId> { None }
fn resolve_render_class(&self, class: ClassId) -> ClassId;

• facet_rows — the value-projected sibling of render_rows: field position i binds to facet byte i per .claude/v3/soa_layout/le-contract.md §3 ("the 12-byte payload is a dumb byte register the ClassView projects"). Positions ≥ 12 are value-slab fields — skipped, never folded (mirrors the FieldMask 64-guard). C2 presence-never-semantics holds: the mask gates which rows exist, never what a byte means.
• resolve_render_class — the zero-fallback render ladder: bespoke card → nearest is_a ancestor with a non-empty field set → return the original class (empty fields() on the result = caller renders the generic facet dump). 16-hop cap + on-stack visited array: cycle- and depth-safe, no allocation beyond the walk, never fails.
• is_a_parent — the taxonomy hop, default None (walk degenerates to identity; OgarClassView wiring from its subClassOf cache is follow-up).

Verification

• cargo test -p lance-graph-contract: class_view 21/21 (7 new), contract lib 822 passing, 0 failures
• cargo clippy -p lance-graph-contract --all-targets -- -D warnings clean; fmt clean
• Regression canary pins existing render_rows behavior unchanged

Board hygiene (same commit)

LATEST_STATE.md Contract Inventory entry + AGENT_LOG.md prepend. EPIPHANIES untouched deliberately — this wires the already-locked E-V3-FACET-4-PLUS-12 §3 register into a projection, no new doctrine.

Consumer notes

Call resolve_render_class(concept) first, then facet_rows on the resolved class. Per le-contract §3b, reading a new tenant lane downstream still owes an ICC/Spearman/Cronbach certification before the reading is trusted — facet_rows hands over bytes positionally, not a validated semantic reading.

Merge order

This PR merges first. The companion q2 PR (cockpit unified card routes + OSINT detail popup) consumes this API via the path dep, and q2's Railway Dockerfile clones lance-graph @ main HEAD — the q2 build only sees this once it's on main.

🤖 Generated with Claude Code

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Generated by Claude Code

Summary by CodeRabbit

• New Features

  • Added support for rendering class facets as value rows, including label, predicate, position, and byte value details.
  • Improved class rendering to follow parent relationships when a class has no direct fields, making output more complete.
  • Exposed the new value-row format for consumers of the contract API.

• Bug Fixes

  • Added safeguards for cycles and depth limits during class resolution, preventing endless traversal.
  • Preserved existing render output when the new facet row support is present.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 2fa94673-c37b-4572-8433-04102fdcb510

📥 Commits

Reviewing files that changed from the base of the PR and between eda867b and b8ac0c8.

📒 Files selected for processing (4)

• .claude/board/AGENT_LOG.md
• .claude/board/LATEST_STATE.md
• crates/lance-graph-contract/src/class_view.rs
• crates/lance-graph-contract/src/lib.rs

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📝 Walkthrough

Walkthrough

This PR extends the ClassView trait in lance-graph-contract with a new ValueRow<'a> struct and three methods: facet_rows (facet-to-value projection), is_a_parent (default None), and resolve_render_class (cycle-safe, hop-capped taxonomy walk). ValueRow is re-exported from lib.rs. Test fixtures and coverage are expanded, and board log files record the change.

Changes

ClassView facet projection and taxonomy resolution

Layer / File(s)	Summary
ValueRow type, facet_rows, and resolve_render_class methods crates/lance-graph-contract/src/class_view.rs, crates/lance-graph-contract/src/lib.rs	Adds ValueRow<'a> struct (label, predicate, position, value), facet_rows for mask/facet-based value projection, default is_a_parent, and resolve_render_class for a cycle-guarded, hop-capped taxonomy walk; re-exports ValueRow from the crate root.
Test fixtures and coverage crates/lance-graph-contract/src/class_view.rs	Extends FakeClasses with extra/parents maps and with_class/with_isa builders, updates is_a_parent and fields implementations, and adds tests for facet binding/skipping, taxonomy ladder resolution, cycle/orphan handling, and a render_rows regression canary.
Board log entries .claude/board/AGENT_LOG.md, .claude/board/LATEST_STATE.md	Appends dated entries documenting the ClassView unified render feature and reported test outcomes.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Possibly related PRs

• AdaWorldAPI/lance-graph#441: Both PRs modify crates/lance-graph-contract/src/class_view.rs, with the earlier PR introducing the base ClassView/render_rows and this PR extending it with facet_rows, ValueRow, and taxonomy resolution.

Poem

A rabbit hops through classes tall,
Following is_a till fields befall,
Twelve bytes of facet, bit by bit,
Rendered rows now snugly fit,
No cycle traps this bunny's stride —
Hop, hop, hooray, the tests all glide! 🐇✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main API extension: unified ClassView rendering with facet value rows and is_a-based render-class resolution.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

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