feat(p10-2): dockerfile-file-v1 chunker (whole-file 1 chunk, symbol <dockerfile>)

Reads entire Dockerfile / Dockerfile.* / *.dockerfile content and emits a
single Chunk with symbol "<dockerfile>", code_lang "dockerfile", line range
1..EOF. Oversize >200 lines splits into line-windows sharing the symbol via
tier2_shared::push_chunks_with_oversize.

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

crates/kebab-chunk/tests/dockerfile_file_v1.rs

@@ -0,0 +1,134 @@
+//! Behavioural tests for `DockerfileFileV1Chunker`.
+//!
+//! Documents are constructed manually (no kebab-parse-code dependency) by
+//! placing the raw Dockerfile text into a single `Block::Code`, mirroring the
+//! pattern used in `k8s_manifest_resource_v1.rs`.
+
+use std::path::PathBuf;
+
+use kebab_chunk::DockerfileFileV1Chunker;
+use kebab_core::{
+    AssetId, Block, CanonicalDocument, ChunkPolicy, Chunker, ChunkerVersion, CodeBlock,
+    CommonBlock, Lang, Metadata, ParserVersion, Provenance, SourceSpan, SourceType, TrustLevel,
+    WorkspacePath, id_for_block, id_for_doc,
+};
+use time::OffsetDateTime;
+
+// ── helpers ──────────────────────────────────────────────────────────────────
+
+fn fixtures_dir() -> PathBuf {
+    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("tests")
+        .join("fixtures")
+}
+
+/// Build a `CanonicalDocument` with a single `Block::Code` containing `dockerfile_text`.
+fn dockerfile_doc(dockerfile_text: &str) -> CanonicalDocument {
+    let wp = WorkspacePath("build/Dockerfile".into());
+    let aid = AssetId("d".repeat(64));
+    let pv = ParserVersion("code-dockerfile-v1".into());
+    let doc_id = id_for_doc(&wp, &aid, &pv);
+
+    let line_count = dockerfile_text.lines().count() as u32;
+    let span = SourceSpan::Code {
+        line_start: 1,
+        line_end: line_count.max(1),
+        symbol: None,
+        lang: Some("dockerfile".into()),
+    };
+    let bid = id_for_block(&doc_id, "code", &[], 0, &span);
+    let block = Block::Code(CodeBlock {
+        common: CommonBlock {
+            block_id: bid,
+            heading_path: vec![],
+            source_span: span,
+        },
+        lang: Some("dockerfile".into()),
+        code: dockerfile_text.to_string(),
+    });
+
+    CanonicalDocument {
+        doc_id,
+        source_asset_id: aid,
+        workspace_path: wp,
+        title: "Dockerfile".into(),
+        lang: Lang("und".into()),
+        blocks: vec![block],
+        metadata: Metadata {
+            aliases: vec![],
+            tags: vec![],
+            created_at: OffsetDateTime::from_unix_timestamp(1_700_000_000).unwrap(),
+            updated_at: OffsetDateTime::from_unix_timestamp(1_700_000_000).unwrap(),
+            source_type: SourceType::Note,
+            trust_level: TrustLevel::Primary,
+            user_id_alias: None,
+            user: Default::default(),
+            repo: Some("kebab".into()),
+            git_branch: Some("main".into()),
+            git_commit: Some("0".repeat(40)),
+            code_lang: Some("dockerfile".into()),
+        },
+        provenance: Provenance { events: vec![] },
+        parser_version: pv,
+        schema_version: 1,
+        doc_version: 1,
+        last_chunker_version: None,
+        last_embedding_version: None,
+    }
+}
+
+fn policy() -> ChunkPolicy {
+    ChunkPolicy {
+        target_tokens: 500,
+        overlap_tokens: 80,
+        respect_markdown_headings: false,
+        chunker_version: ChunkerVersion("dockerfile-file-v1".into()),
+    }
+}
+
+// ── tests ─────────────────────────────────────────────────────────────────────
+
+/// A simple 5-line Dockerfile fixture must emit exactly 1 chunk with the
+/// correct symbol, lang, and line range.
+#[test]
+fn dockerfile_emits_single_chunk() {
+    let fixture_path = fixtures_dir().join("sample.dockerfile");
+    let text = std::fs::read_to_string(&fixture_path)
+        .unwrap_or_else(|e| panic!("cannot read fixture {}: {e}", fixture_path.display()));
+
+    let doc = dockerfile_doc(&text);
+    let chunks = DockerfileFileV1Chunker
+        .chunk(&doc, &policy())
+        .expect("chunk");
+
+    assert_eq!(
+        chunks.len(),
+        1,
+        "expected 1 chunk, got {}: {chunks:#?}",
+        chunks.len()
+    );
+
+    // Inspect the Chunk's source_spans for symbol / lang / line range.
+    let span = chunks[0].source_spans.first().expect("at least one span");
+    match span {
+        SourceSpan::Code {
+            line_start,
+            line_end,
+            symbol,
+            lang,
+        } => {
+            assert_eq!(*line_start, 1, "line_start must be 1");
+            assert_eq!(*line_end, 5, "line_end must be 5 (5-line fixture)");
+            assert_eq!(
+                symbol.as_deref(),
+                Some("<dockerfile>"),
+                "symbol must be '<dockerfile>'"
+            );
+            assert_eq!(lang.as_deref(), Some("dockerfile"), "lang must be 'dockerfile'");
+        }
+        other => panic!("expected SourceSpan::Code, got {other:?}"),
+    }
+
+    // Verify chunker_version label.
+    assert_eq!(chunks[0].chunker_version.0, "dockerfile-file-v1");
+}