feat(runtime): add resident Wasmtime actor runtime

- define versioned service and clock WIT contracts
- enforce import allowlists, fuel, epoch, memory, I/O, and mailbox limits
- keep one Store and Component Instance resident per serial Actor
- add echo, counter, fault, spin, and capability probe components
- cover lifecycle, concurrency, sandbox, and fault recovery behavior

Cargo.toml

@@ -1,8 +1,15 @@
 [workspace]
 members = [
   "crates/wasmeld-package",
+  "crates/wasmeld-runtime",
+  "components/echo",
+  "components/counter",
+  "components/fault",
+  "components/spin",
+  "components/clock-probe",
+  "components/wasi-clock-probe",
 ]
-default-members = ["crates/wasmeld-package"]
+default-members = ["crates/wasmeld-runtime"]
 resolver = "2"
 
 [workspace.package]
@@ -18,6 +25,9 @@ semver = "1.0.28"
 sha2 = "0.10.9"
 thiserror = "2.0.17"
 toml = "0.9.8"
+wasmtime = { version = "=41.0.0", default-features = false, features = ["component-model", "cranelift", "runtime", "std"] }
+wasmtime-wasi = { version = "=41.0.0", default-features = false, features = ["p2"] }
+wit-bindgen = "=0.41.0"
 wit-component = "=0.243.0"
 wit-parser = "0.243.0"
 zip = { version = "2.4.2", default-features = false, features = ["deflate"] }