feat(federation): activate verified corpus graphs (#464)

## Stack

1. #462 — ratify graph decisions
2. #463 — graph foundation
3. **This PR — activate the verified graph engine**
4. #465 — profile guidance and DecisionGrounding evidence

## What this implements

- manifest v2 with multiple direct parents and bounded recursive DAG
composition
- independently verified physical routes, cycle/divergent-pin detection,
and diamond deduplication
- global `corpus.source::canonical-id` resolution with source-contextual
aliases
- equal cross-source IDs as deterministic ambiguity rather than
precedence
- explicit Decision-backed override chains and diamond convergence
- one catalog/effective/root-local model across validation, resolution,
retrieval, routing, gate, Sentry, exports, MCP, and audit
- closure generation v3 and isolated `store/v3` persistence with
fail-closed freshness and corruption repair
- complete source/layer/pin, override-chain, and topology-route
provenance
- read-only enforcement across every direct, transitive, and duplicate
materialisation route
- additive viewer/documents/graph exports and source-aware Portal
navigation
- exact v1 and no-manifest compatibility paths

## Hardening

The implementation uses stable captured bytes throughout digesting,
parsing, validation, composition, persistence, and serving. It rejects
unsafe YAML, symlink/reparse traversal, hard-linked inherited files,
mount boundaries, path escapes, stale pins, invalid topology, and unsafe
output/cache targets.

## Validation

- `cargo test --workspace --all-targets --locked --no-fail-fast` —
passed
- `cargo clippy --workspace --all-targets --locked -- -D warnings` —
passed
- graph CLI contract — 9/9
- graph MCP contract — 5/5
- v1 federation CLI — 14/14
- v1 federation MCP — 8/8
- `decided validate decisions/` — 468 valid, 0 invalid, 12 skipped
- `decided relationships decisions/ --validate` — 3,055 checked, 0
issues
- `decided gate decisions/ --json` — 0 blocking, 134 existing advisories
- `decided review decisions/ --json` — 508 non-blocking issues, health
96
- agent-rules drift check — in sync
- Linux, Windows, and macOS cross-platform certification — passed

Review and merge after #462 and #463.

Closes #270
Closes #272

Author: tcballard

rust/Cargo.lock

@@ -16,3 +16,6 @@ publish = ["crates-io"]
 rac-engine = { package = "asdecided-core", version = "=0.28.0", path = "../rac-engine" }
 serde = { version = "1", features = ["derive"] }
 serde_json = { version = "1", features = ["preserve_order"] }
+
+[dev-dependencies]
+sha2 = "0.10"

rust/decided-mcp/Cargo.toml

@@ -146,6 +146,14 @@ impl GraphView {
         )
     }
 
+    pub fn from_graph(corpus: &rac_engine::graph_composition::GraphComposition) -> Self {
+        Self::new_with_history(
+            corpus.identity_index(),
+            corpus.relationships(),
+            Some(corpus.catalog_relationships_compatible()),
+        )
+    }
+
     pub fn new(entries: Vec<IndexEntry>, relationships: Vec<Relationship>) -> Self {
         Self::new_with_history(entries, relationships, None)
     }
@@ -703,6 +711,34 @@ impl GraphCache {
         self.view.as_ref().expect("federated graph view built")
     }
 
+    pub fn view_for_graph(
+        &mut self,
+        generation: &str,
+        corpus: &rac_engine::graph_composition::GraphComposition,
+    ) -> &GraphView {
+        if self.federated_generation.as_deref() != Some(generation)
+            || self.generation.is_some()
+            || self.view.is_none()
+        {
+            let started = rac_engine::timing::start();
+            let replacement = GraphView::from_graph(corpus);
+            rac_engine::timing::emit_since(
+                "graph.view_build",
+                started,
+                &[
+                    ("entries", replacement.entry_count() as u64),
+                    ("relationships", replacement.relationship_count() as u64),
+                    ("payload_bytes", replacement.estimated_payload_bytes() as u64),
+                ],
+            );
+            self.view = Some(replacement);
+            self.generation = None;
+            self.federated_generation = Some(generation.to_string());
+            self.builds += 1;
+        }
+        self.view.as_ref().expect("graph federation view built")
+    }
+
     #[cfg(test)]
     pub fn builds(&self) -> u64 {
         self.builds