lgj-abi: bind the real OGAR ClassView provider behind a feature

.claude/board/EPIPHANIES.md

@@ -4,6 +4,43 @@
 > `**Status:**`/`**Confidence:**` line. A correction gets its own new,
 > dated entry that references the one it corrects — the storno rule.
 
+## 2026-08-27 — E-BINDING-A-REAL-PROVIDER-MEASURES-THE-FIXTURE-1
+
+**Status:** FINDING — measured, pinned by a test rather than asserted.
+**Confidence:** High. Both halves are numbers, and the disable-run is
+red-then-green on five tests.
+
+Binding the real `ClassView` provider (`OgarClassView`) behind
+`--features ogar-classview` did not make the hop *better*. It made the hop
+*empty* — and that emptiness is the most useful thing the wiring produced.
+
+The provider itself is correct and discriminating: 98 registered classes,
+**12 distinct** participation masks where the fixture answered one. But the
+generated row store's classid domain is `0..16`
+(`ROWSTORE_CLASS_CARDINALITY`) while every vocabulary classid is `>= 0x0100`
+— **disjoint**. So a generated store under a real provider traverses nothing,
+for every classid in its own domain.
+
+**The generalizable part.** A fixture with a plausible answer for every input
+(`FieldMask::FULL`) is indistinguishable from a bound provider until you bind
+one. `FULL` is the answer that never disagrees, which is exactly why it
+cannot be falsified in place. The measurement that mattered was not "does
+the provider work" — it was **binding it and reading what the rest of the
+system then failed to do**. The seam was declared closed-enough for two
+waves because nothing in the suite could tell the two providers apart.
+
+**Consequence, stated rather than fixed here:** the remaining fixture is the
+row CONTENT, not the layout or the kernels. Replacing `RowStore::generate`
+with Lance-loaded SoA rows is what makes the bound provider observable
+end-to-end; until then the feature is a correct provider over rows it has no
+classes for.
+
+**Discipline note.** Two fixture-semantics tests had to be gated OFF under
+the feature. Neither was deleted: each got a paired ON twin asserting the
+CONTRASTING fact on the same inputs (all-32 vs none; 19/29 vs empty), so the
+gate reads as evidence of a changed answer rather than as a suppressed
+failure.
+
 ## 2026-08-26 — E-ONE-SUBSTRATE-FIVE-GLOVES-GHIDRA-IS-THE-GLOVE-NOT-THE-MODEL-1
 
 **Status:** DOCTRINE — [OPERATOR-FRAMED]. The "what is it FOR" that the

.claude/board/LATEST_STATE.md

@@ -1,3 +1,36 @@
+## 2026-08-27 — the REAL ClassView provider is bound, and it measures the fixture's reach
+
+The `ClassView` provider seam (§4-NG3, "a real ontology/cache provider is a
+NAMED SEAM") is no longer only named. `ogar_class_view::OgarClassView` — the
+ontology-backed provider over `ogar_vocab` — is bound behind a new
+`ogar-classview` feature on `native/lgj-abi`, and `edge_participation` derives
+from each class's real field basis instead of the fixture's constant.
+
+- **The provider discriminates, measured.** `examples/classview_census.rs`:
+  **98 registered classes, 12 distinct participation masks** (field counts
+  0–13), against the fixture's single `0xFFFF_FFFF` for all 98. An
+  unregistered classid participates in **nothing** — an unknown class is not
+  a licence to traverse every facet.
+- **The `[patch]` was load-bearing, not cosmetic.** `ogar-class-view` pulls
+  `lance-graph-contract` by git branch; this crate pulls it by path, and
+  cargo does not unify a git SourceId with a path SourceId — without the
+  patch the build carries two `lance-graph-contract` crates and therefore
+  two incompatible `ClassView` traits. Verified: `cargo tree` shows one.
+- **What binding it EXPOSED, and this is the finding.** The generated row
+  store draws classids from `0..16` (`ROWSTORE_CLASS_CARDINALITY`); every
+  vocabulary classid is `>= 0x0100`. The two domains are **disjoint**, so a
+  generated store under the real provider hops nothing. The remaining
+  fixture is the row CONTENT — Lance-loaded SoA rows are what make the bound
+  provider observable end-to-end. Pinned by
+  `hop_under_the_real_provider_narrows_by_class`, not left in prose.
+- **Default is unchanged and proven so.** Feature OFF: 134/134 rust, 447/447
+  Java (304 core + 143 consumer) — the same numbers as before. Feature ON:
+  136/136. Two fixture-semantics tests are gated OFF under the feature and
+  each has a paired ON twin asserting the CONTRASTING fact, so nothing was
+  merely disabled. Five tests red-then-green under the disable
+  (`edge_participation`'s ogar arm returns `FULL`). G11 fence green:
+  `class_view`, `canonical_node`, `ontology`, `facet` only.
+
 ## 2026-08-25 — the Ghidra end of the R2IL arc: seam verified, vocabulary measured
 
 Working the `r2il-machine-semantic-contract-v1` plan (lance-graph, PR #1027,

native/lgj-abi/Cargo.toml

@@ -43,6 +43,12 @@ ndarray = { path = "../../../ndarray", default-features = false, features = ["st
 # this crate consumes, and the crate compiles fine without them.
 lance-graph-contract = { path = "../../../lance-graph/crates/lance-graph-contract", default-features = false }
 
+# The REAL ClassView provider (OGAR Core). `FixtureClassView` answers the same
+# 32 facets for every classid; `OgarClassView` walks `ogar_vocab`'s promoted
+# classes and gives a genuine per-class field basis -- attributes AND
+# associations -- which is what makes `edge_participation` discriminate.
+ogar-class-view = { path = "../../../OGAR/crates/ogar-class-view", optional = true }
+
 [profile.release]
 opt-level = 3
 lto = "thin"
@@ -55,3 +61,18 @@ codegen-units = 1
 
 [profile.dev]
 # Same rule as release: no panic = "abort".
+
+[features]
+# Bind the real OGAR ClassView instead of the fixture. OFF by default: the
+# generated row store's classid domain (0..16) is disjoint from the
+# vocabulary's (>= 0x0100), so binding it changes what every hop answers --
+# see `class_view_provider`'s module docs.
+ogar-classview = ["dep:ogar-class-view"]
+
+# ogar-class-view pulls `lance-graph-contract` by git branch; this crate pulls
+# it by path. Cargo does NOT unify a git source with a path source, so without
+# this patch the build carries TWO `lance-graph-contract` crates and therefore
+# two incompatible `ClassView` traits -- the same SourceId trap recorded in
+# tesseract-rs for `ogar-doc-ir`. The patch collapses both onto the local path.
+[patch."https://github.com/AdaWorldAPI/lance-graph"]
+lance-graph-contract = { path = "../../../lance-graph/crates/lance-graph-contract" }

native/lgj-abi/examples/classview_census.rs

@@ -0,0 +1,34 @@
+//! What the REAL ClassView provider answers, versus the fixture's constant.
+//!
+//! `cargo run --features ogar-classview --example classview_census`
+fn main() {
+    #[cfg(not(feature = "ogar-classview"))]
+    println!("build with --features ogar-classview");
+
+    #[cfg(feature = "ogar-classview")]
+    {
+        use lance_graph_contract::class_view::ClassView;
+        use ogar_class_view::OgarClassView;
+        use std::collections::BTreeMap;
+
+        let view = OgarClassView::new();
+        let ids: Vec<u16> = view.known_class_ids().collect();
+        let mut hist: BTreeMap<usize, usize> = BTreeMap::new();
+        for c in &ids {
+            *hist.entry(view.fields(*c).len().min(32)).or_default() += 1;
+        }
+        println!("registered classes : {}", ids.len());
+        println!(
+            "distinct field counts (= distinct participation masks): {}",
+            hist.len()
+        );
+        println!("\n  fields  classes");
+        for (k, n) in &hist {
+            println!("  {k:>6}  {n:>7}");
+        }
+        println!(
+            "\nfixture would answer 0xFFFFFFFF (32 facets) for ALL {} classes.",
+            ids.len()
+        );
+    }
+}