feat(defi/order-book): add order-book example with critbit slab matching engine

README.md

@@ -23,6 +23,12 @@ Constant product AMM (x·y=k) — create liquidity pools, deposit and withdraw l
 
 [⚓ Anchor](./tokens/token-swap/anchor) [💫 Quasar](./tokens/token-swap/quasar)
 
+### Central Limit Order Book
+
+Order-book exchange — users post limit bids and asks at chosen prices, tokens are locked in program vaults, and orders cross against the opposing side using price-time priority. Fees route to a dedicated fee vault, maker/taker proceeds land in unsettled balances, and funds are withdrawn via `settle_funds`. A minimal teaching example of the mechanics behind Openbook and Phoenix.
+
+[⚓ Anchor](./defi/order-book/anchor)
+
 ### Escrow
 
 Peer-to-peer OTC trade — one user deposits token A and specifies how much token B they want. A counterparty fulfills the offer and both sides receive their tokens atomically.

defi/order-book/anchor/.gitignore

@@ -0,0 +1,7 @@
+.anchor
+.DS_Store
+target
+**/*.rs.bk
+node_modules
+test-ledger
+.yarn

defi/order-book/anchor/Anchor.toml

@@ -0,0 +1,20 @@
+[toolchain]
+# Pin Solana to the version used across the repo's Anchor 1.0 examples so the
+# bundled test validator and BPF toolchain stay in lock-step.
+solana_version = "3.1.8"
+
+[features]
+resolution = true
+skip-lint = false
+
+[programs.localnet]
+order_book = "C69UJ8irfmHq5ysyLek7FKApHR86FBeupiz4JnoyPzzx"
+
+[provider]
+cluster = "Localnet"
+wallet = "~/.config/solana/id.json"
+
+[scripts]
+# LiteSVM Rust tests live under `programs/order-book/tests/` and include the built
+# `.so` via `include_bytes!`, so a fresh `anchor build` must run first.
+test = "cargo test"

defi/order-book/anchor/Cargo.toml

@@ -0,0 +1,13 @@
+[workspace]
+members = ["programs/*"]
+resolver = "2"
+
+[profile.release]
+overflow-checks = true
+lto = "fat"
+codegen-units = 1
+
+[profile.release.build-override]
+opt-level = 3
+incremental = false
+codegen-units = 1