feat: FDKMS foundation — document ingestion, Xero OAuth2, LLM vision, filesystem metadata

Adds the Financial Document Knowledge Management System foundation across
four new/updated crates: document model (DocType, XeroLink, DocumentRecord),
#tag newtypes, sidecar+xattr filesystem metadata backends, blocking Xero
PKCE OAuth2 client, blocking OpenAI-compatible LLM client (receipt/document
OCR + transaction classification), XeroService MCP bridge, and ledgerr_xero
as the 8th MCP tool. Regenerates docs and scripts from Rust contract source.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Claude Sonnet (coordinator)

Cargo.lock

@@ -2,6 +2,8 @@
 members = [
   "crates/ledger-core",
   "crates/ledgerr-mcp",
+  "crates/ledgerr-xero",
+  "crates/ledgerr-llm",
   "xtask",
 ]
 resolver = "2"
@@ -13,6 +15,15 @@ version = "1.4.0"
 
 [workspace.dependencies]
 rust_xlsxwriter = "0.94.0"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+thiserror = "2"
+tokio = { version = "1", features = ["full"] }
+reqwest = { version = "0.12", features = ["blocking", "json", "rustls-tls"], default-features = false }
+chrono = { version = "0.4", features = ["serde"] }
+rust_decimal = { version = "1.41.0", features = ["serde"] }
+blake3 = "1.8.3"
+tracing = "0.1"
 
 [workspace.lints.rust]
 unsafe_code = "forbid"

Cargo.toml

@@ -6,13 +6,18 @@ license.workspace = true
 
 [dependencies]
 serde = { version = "1", features = ["derive"] }
+serde_json = "1"
 toml = "0.8"
 rust_xlsxwriter = { workspace = true }
 calamine = "0.34"
 thiserror = "2"
 blake3 = "1"
 rhai = "1.24.0"
 
+# filesystem metadata — xattr on Linux; sidecar fallback is pure std
+[target.'cfg(target_os = "linux")'.dependencies]
+xattr = "1"
+
 [lints]
 workspace = true