feat(cli): wire sunbeam-net into sunbeam connect/disconnect/vpn

Adds the foreground VPN client commands. The daemon runs in-process
inside the CLI for the lifetime of `sunbeam connect` — no separate
background daemon yet, that can come later if needed.

- Cargo.toml: add sunbeam-net as a workspace dep, plus hostname/whoami
  for building a per-machine netmap label like "sienna@laptop"
- src/config.rs: new `vpn-url` and `vpn-auth-key` fields on Context
- src/cli.rs: `Connect`, `Disconnect`, and `Vpn { Status }` verbs
- src/vpn_cmds.rs: command handlers
  - cmd_connect reads VPN config from the active context, starts the
    daemon at ~/.sunbeam/vpn, polls for Running, then blocks on ^C
    before calling DaemonHandle::shutdown
  - cmd_disconnect / cmd_vpn_status are placeholders that report based
    on the control socket; actually talking to a backgrounded daemon
    needs an IPC client (not yet exposed from sunbeam-net)
- src/workflows/mod.rs: `..Default::default()` on Context literals so
  the new fields don't break the existing tests

Cargo.lock

@@ -1471,7 +1471,7 @@ dependencies = [
  "cfg-if",
  "js-sys",
  "libc",
- "wasi",
+ "wasi 0.11.1+wasi-snapshot-preview1",
  "wasm-bindgen",
 ]
 
@@ -2463,7 +2463,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a69bcab0ad47271a0234d9422b131806bf3968021e5dc9328caf2d4cd58557fc"
 dependencies = [
  "libc",
- "wasi",
+ "wasi 0.11.1+wasi-snapshot-preview1",
  "windows-sys 0.61.2",
 ]
 
@@ -2586,6 +2586,24 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830b246a0e5f20af87141b25c173cd1b609bd7779a4617d6ec582abaf90870f3"
 
+[[package]]
+name = "objc2-core-foundation"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a180dd8642fa45cdb7dd721cd4c11b1cadd4929ce112ebd8b9f5803cc79d536"
+dependencies = [
+ "bitflags 2.11.0",
+]
+
+[[package]]
+name = "objc2-system-configuration"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7216bd11cbda54ccabcab84d523dc93b858ec75ecfb3a7d89513fa22464da396"
+dependencies = [
+ "objc2-core-foundation",
+]
+
 [[package]]
 name = "object"
 version = "0.37.3"
@@ -4158,7 +4176,7 @@ dependencies = [
  "thiserror 2.0.18",
  "tracing",
  "uuid",
- "whoami",
+ "whoami 1.6.1",
 ]
 
 [[package]]
@@ -4197,7 +4215,7 @@ dependencies = [
  "thiserror 2.0.18",
  "tracing",
  "uuid",
- "whoami",
+ "whoami 1.6.1",
 ]
 
 [[package]]
@@ -4334,6 +4352,7 @@ dependencies = [
  "flate2",
  "futures",
  "hmac",
+ "hostname",
  "indicatif",
  "k8s-openapi",
  "kube",
@@ -4351,6 +4370,7 @@ dependencies = [
  "serde_json",
  "serde_yaml",
  "sha2",
+ "sunbeam-net",
  "sunbeam-sdk",
  "tar",
  "tempfile",
@@ -4364,6 +4384,7 @@ dependencies = [
  "wfe-core",
  "wfe-sqlite",
  "wfe-yaml",
+ "whoami 2.1.1",
  "wiremock",
 ]
 
@@ -5028,6 +5049,15 @@ version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
+[[package]]
+name = "wasi"
+version = "0.14.7+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "883478de20367e224c0090af9cf5f9fa85bed63a95c1abf3afc5c083ebc06e8c"
+dependencies = [
+ "wasip2",
+]
+
 [[package]]
 name = "wasip2"
 version = "1.0.2+wasi-0.2.9"
@@ -5052,6 +5082,15 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b8dad83b4f25e74f184f64c43b150b91efe7647395b42289f38e50566d82855b"
 
+[[package]]
+name = "wasite"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "66fe902b4a6b8028a753d5424909b764ccf79b7a209eac9bf97e59cda9f71a42"
+dependencies = [
+ "wasi 0.14.7+wasi-0.2.4",
+]
+
 [[package]]
 name = "wasm-bindgen"
 version = "0.2.114"
@@ -5272,7 +5311,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d4a4db5077702ca3015d3d02d74974948aba2ad9e12ab7df718ee64ccd7e97d"
 dependencies = [
  "libredox",
- "wasite",
+ "wasite 0.1.0",
+]
+
+[[package]]
+name = "whoami"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6a5b12f9df4f978d2cfdb1bd3bac52433f44393342d7ee9c25f5a1c14c0f45d"
+dependencies = [
+ "libc",
+ "libredox",
+ "objc2-system-configuration",
+ "wasite 1.0.2",
+ "web-sys",
 ]
 
 [[package]]