feat(wire): search_hit.v1 + citation.v1 require indexed_at + stale (fb-32)

Additive minor — schema_version unchanged. Existing v1 consumers
that ignore unknown fields stay compatible; consumers that validate
strictly will reject pre-fb-32 payloads, which matches the wire
contract escape hatch (recipient version >= producer required).

Cross-task placeholders: kebab-eval / kebab-tui synthetic test
fixtures pin UNIX_EPOCH + stale=false (same pattern as
hybrid.rs / vector.rs). These don't exercise staleness — Task 11
adds dedicated TUI staleness rendering tests.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-eval/src/metrics.rs

@@ -444,6 +444,10 @@ mod tests {
             index_version: IndexVersion(format!("idx@{rank}")),
             embedding_model: None,
             chunker_version: ChunkerVersion("test@1".into()),
+            // fb-32: synthetic eval fixtures don't exercise staleness;
+            // pin UNIX_EPOCH + stale=false so hits stay deterministic.
+            indexed_at: OffsetDateTime::UNIX_EPOCH,
+            stale: false,
         }
     }
 
@@ -479,6 +483,9 @@ mod tests {
                     end: 1,
                     section: None,
                 },
+                // fb-32: synthetic eval citations don't exercise staleness.
+                indexed_at: OffsetDateTime::UNIX_EPOCH,
+                stale: false,
             }).collect(),
             grounded,
             refusal_reason: None,

crates/kebab-eval/tests/metrics_and_compare.rs

@@ -82,6 +82,10 @@ fn hit(rank: u32, chunk_id: &str, doc_id: &str) -> SearchHit {
         index_version: IndexVersion("idx@1".into()),
         embedding_model: None,
         chunker_version: ChunkerVersion("test@1".into()),
+        // fb-32: synthetic eval fixtures don't exercise staleness;
+        // pin UNIX_EPOCH + stale=false so hits stay deterministic.
+        indexed_at: OffsetDateTime::UNIX_EPOCH,
+        stale: false,
     }
 }
 

crates/kebab-tui/tests/ask.rs

@@ -42,6 +42,10 @@ fn make_answer(grounded: bool, refusal: Option<RefusalReason>, body: &str) -> An
                 end: 14,
                 section: Some("Section A".into()),
             },
+            // fb-32: TUI ask test fixture pinned to UNIX_EPOCH + stale=false;
+            // staleness rendering covered in dedicated tests (Task 11).
+            indexed_at: OffsetDateTime::UNIX_EPOCH,
+            stale: false,
         }],
         grounded,
         refusal_reason: refusal,

crates/kebab-tui/tests/search.rs

@@ -51,6 +51,10 @@ fn make_hit(rank: u32, path: &str, snippet: &str, citation: Citation) -> SearchH
         index_version: IndexVersion("v1".into()),
         embedding_model: Some(EmbeddingModelId("multilingual-e5-small".into())),
         chunker_version: ChunkerVersion("md-heading-v1".into()),
+        // fb-32: TUI search test fixtures pinned to UNIX_EPOCH + stale=false;
+        // staleness rendering covered in dedicated tests (Task 11).
+        indexed_at: time::OffsetDateTime::UNIX_EPOCH,
+        stale: false,
     }
 }
 

docs/wire-schema/v1/citation.schema.json

@@ -4,7 +4,7 @@
   "title": "Citation v1",
   "description": "Stub schema — declares the schema_version label and the always-present fields. Variant-discriminated property validation lands in a later phase.",
   "type": "object",
-  "required": ["schema_version", "kind", "path", "uri"],
+  "required": ["schema_version", "kind", "path", "uri", "indexed_at", "stale"],
   "properties": {
     "schema_version": { "const": "citation.v1" },
     "kind": { "enum": ["line", "page", "region", "caption", "time"] },
@@ -14,6 +14,8 @@
     "page":    { "type": "object" },
     "region":  { "type": "object" },
     "caption": { "type": "object" },
-    "time":    { "type": "object" }
+    "time":    { "type": "object" },
+    "indexed_at": { "type": "string", "format": "date-time" },
+    "stale":      { "type": "boolean" }
   }
 }

docs/wire-schema/v1/search_hit.schema.json

@@ -16,7 +16,9 @@
     "citation",
     "retrieval",
     "index_version",
-    "chunker_version"
+    "chunker_version",
+    "indexed_at",
+    "stale"
   ],
   "properties": {
     "schema_version": { "const": "search_hit.v1" },
@@ -33,6 +35,8 @@
     "retrieval":       { "type": "object" },
     "index_version":   { "type": "string" },
     "embedding_model": { "type": ["string", "null"] },
-    "chunker_version": { "type": "string" }
+    "chunker_version": { "type": "string" },
+    "indexed_at":      { "type": "string", "format": "date-time" },
+    "stale":           { "type": "boolean" }
   }
 }