Description

PR #3624 introduced a wildcard match arm in `gonka/tests.rs:467` that triggers `clippy::match_wildcard_for_single_variants`, breaking `cargo clippy --workspace --features full -- -D warnings`.

Reproduction Steps

1. `cargo clippy --all-targets --workspace --features full -- -D warnings`
2. Observe:
   ```
   error: wildcard matches only a single variant and will also match any future added variants
   --> crates/zeph-llm/src/gonka/tests.rs:467:9
   |
   467 | other => panic!("expected ToolUse, got: {other:?}"),
   | ^^^^^ help: try: `other @ ChatResponse::Text(_)`
   ```

Expected Behavior

Zero clippy warnings/errors with `-D warnings`.

Actual Behavior

Clippy error in test code blocks CI check.

Fix

Change line 467 in `crates/zeph-llm/src/gonka/tests.rs`:
```rust
// Before:
other => panic!("expected ToolUse, got: {other:?}"),
// After:
other @ ChatResponse::Text(_) => panic!("expected ToolUse, got: {other:?}"),
```
Or use a more exhaustive match that names all variants.

Environment

• Version: 0.20.1 (HEAD 3b1cc09)
• Features: full
• Introduced by: PR feat(zeph-llm): GonkaProvider chat_with_tools and chat_typed (#3612) #3624