feat(p10-1a-2): add internal SourceSpan::Code variant + design §3.4 sync

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

crates/kebab-core/src/document.rs

@@ -142,6 +142,18 @@ pub enum SourceSpan {
         start_ms: u64,
         end_ms: u64,
     },
+    /// p10-1A-2: AST-unit span for code ingest. Internal storage shape
+    /// (chunks.source_spans_json) — `citation_helper` maps this to the
+    /// wire `Citation::Code` (added 1A-1). `symbol` is the per-language
+    /// self-reference path (design §3.4); `<top-level>` / `<module>` for
+    /// glue regions, never null for an identified unit. `lang` is the
+    /// canonical code_lang.
+    Code {
+        line_start: u32,
+        line_end: u32,
+        symbol: Option<String>,
+        lang: Option<String>,
+    },
 }
 
 // ── Forward-declared stubs (§3.7a). Bodies are final per design. ────────
@@ -195,6 +207,24 @@ mod tests {
     /// previously failed at serde runtime because `tag = "kind"` cannot
     /// describe a newtype carrying a non-struct value. The struct-variant
     /// shape used here is the §9 schema migration.
+    #[test]
+    fn source_span_code_round_trips_and_tags_lowercase() {
+        let s = SourceSpan::Code {
+            line_start: 10,
+            line_end: 42,
+            symbol: Some("foo::Bar::baz".to_string()),
+            lang: Some("rust".to_string()),
+        };
+        let v = serde_json::to_value(&s).unwrap();
+        assert_eq!(v["kind"], "code");
+        assert_eq!(v["line_start"], 10);
+        assert_eq!(v["line_end"], 42);
+        assert_eq!(v["symbol"], "foo::Bar::baz");
+        assert_eq!(v["lang"], "rust");
+        let back: SourceSpan = serde_json::from_value(v).unwrap();
+        assert_eq!(back, s);
+    }
+
     #[test]
     fn inline_serde_round_trip() {
         let cases = vec![

crates/kebab-search/src/citation_helper.rs

@@ -49,6 +49,13 @@ pub(crate) fn citation_from_first_span(
             end_ms: *end_ms,
             speaker: None,
         },
+        // TODO(p10-1a-2 Task 3): map to Citation::Code
+        Some(SourceSpan::Code { .. }) => Citation::Line {
+            path,
+            start: 1,
+            end: 1,
+            section,
+        },
         // Byte-spans don't have a Citation variant. Fall back to a
         // Line citation pointing at the document head — better than
         // fabricating a position. Spans-empty falls into the same

crates/kebab-tui/src/inspect.rs

@@ -455,6 +455,15 @@ fn describe_span(span: &kebab_core::SourceSpan) -> String {
         SourceSpan::Time { start_ms, end_ms } => {
             format!("Time {start_ms}-{end_ms} ms")
         }
+        SourceSpan::Code {
+            line_start,
+            line_end,
+            symbol,
+            ..
+        } => match symbol {
+            Some(sym) => format!("Code {line_start}-{line_end} ({sym})"),
+            None => format!("Code {line_start}-{line_end}"),
+        },
     }
 }
 

docs/superpowers/specs/2026-04-27-kebab-final-form-design.md

@@ -565,6 +565,7 @@ pub enum SourceSpan {
     Page   { page: u32, char_start: Option<u32>, char_end: Option<u32> },
     Region { x: u32, y: u32, w: u32, h: u32 },
     Time   { start_ms: u64, end_ms: u64 },
+    Code   { line_start: u32, line_end: u32, symbol: Option<String>, lang: Option<String> }, // p10-1A-2: internal code-unit span (see tasks/p10/p10-1a-2)
 }
 ```