buzz agents draft-create panics: rustls CryptoProvider not installed

### What happened
`buzz agents draft-create` panics immediately (exit 101) on every invocation. `buzz agents draft-update` shares the code path and is expected to fail the same way. Other relay-networked commands (`channels create`, `channels add-member`, `messages send`) work fine, so the TLS stack is fine generally — the panic is specific to the agent-draft path.

### Repro
```
buzz agents draft-create --channel --display-name "Test" --system-prompt "test"
```

### Panic
```
thread 'main' panicked at rustls-0.23.42/src/crypto/mod.rs:249:14:
Could not automatically determine the process-level CryptoProvider from Rustls
crate features. Call CryptoProvider::install_default() before this point to select
a provider manually, or make sure exactly one of the 'aws-lc-rs' and 'ring'
features is enabled.
```

### Likely cause
The draft path builds a rustls HTTPS client without a process-level `CryptoProvider` installed (two providers enabled, or none — so auto-select fails). The relay path presumably installs one or uses a different client, which is why messaging/channel commands succeed.

### Suggested fix
Call `CryptoProvider::install_default()` once at startup (e.g. `aws_lc_rs::default_provider().install_default()`), or pin exactly one rustls provider feature in the crate that builds the draft client.