Stand up the Cargo workspace (Rust 2024 / resolver=3) with the kb-core
crate per the frozen design (§3, §4, §7, §10). kb-core has zero
deps on other kb-* crates and exposes:

- Newtype IDs (AssetId / DocumentId / BlockId / ChunkId / EmbeddingId /
  IndexId) with Display + FromStr that reject anything but 32 lower-hex.
- id_from + id_for_{asset,doc,block,chunk,embedding,index} per §4.2;
  pinned hex test values computed via an independent JCS+blake3 tool.
- CanonicalDocument, Block (8 variants), SourceSpan, Inline (§3.4).
- Citation (5 variants) with W3C Media Fragments to_uri / parse;
  round-trip property holds for every variant.
- Metadata + Provenance (§3.6); SearchQuery / SearchHit / RetrievalDetail
  (§3.7); DocFilter / DocSummary mirrors of wire §2.5.
- Answer / AnswerCitation / RefusalReason / ModelRef (§3.8).
- IngestReport, JobRepo support types, VectorRecord / VectorHit.
- Component traits (SourceConnector / Extractor / Chunker / Embedder /
  Retriever / LanguageModel / DocumentStore / VectorStore / JobRepo)
  plus their input helpers (SourceScope / ExtractContext / ChunkPolicy
  / EmbeddingInput / GenerateRequest / TokenChunk / FinishReason).
- CoreError (§10).
- nfc + to_posix helpers (§4.1, §6.6).

20 unit tests cover ID determinism (1000-run regression), key-order
invariance, two pinned hex values, newtype rejection of bad input,
Citation round-trip for all 5 variants, and to_posix collapsing +
Korean NFC.

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

@@ -0,0 +17,4 @@
+
+/// Initialize tracing. Returns a guard to keep alive until exit. Idempotent
+/// — a second call is a no-op.
+pub fn init(level: LogLevel) -> Result<Option<WorkerGuard>> {

@@ -0,0 +10,4 @@
+//! Future tasks (P1-5, P3, P4, P5) replacing stub `bail!` paths must call
+//! these helpers from the relevant CLI subcommand handler before
+//! `serde_json::to_string`.
+//!

@@ -0,0 +8,4 @@
+description   = "Config schema + XDG path resolution"
+
+[dependencies]
+kb-core      = { path = "../kb-core" }

@@ -0,0 +196,4 @@
+            }
+            // Match a small, intentional whitelist for P0 — full env→config
+            // mapping lands when the rest of the schema is wired up.
+            match k.as_str() {

@@ -0,0 +88,4 @@
+    /// `section = None` and `model = ""` for the relevant variants.
+    /// Round-trip property holds for citations whose non-URI fields are at
+    /// their default values (see test).
+    pub fn parse(s: &str) -> Result<Self> {

@@ -0,0 +89,4 @@
+    /// Round-trip property holds for citations whose non-URI fields are at
+    /// their default values (see test).
+    pub fn parse(s: &str) -> Result<Self> {
+        let (path_str, frag) = match s.rsplit_once('#') {

@@ -0,0 +51,4 @@
+            s.len()
+        )));
+    }
+    if !s.bytes().all(|b| matches!(b, b'0'..=b'9' | b'a'..=b'f')) {

@@ -0,0 +283,4 @@
+        //   → cec9353553efb238a7919d38d3e148f1...
+        let id = id_for_asset("deadbeef");
+        assert_eq!(id.0, "cec9353553efb238a7919d38d3e148f1");
+    }

@@ -0,0 +1,70 @@
+//! `kb-core` — frozen domain types, traits, and ID recipe.