⚡ Bolt: [performance improvement] remove vector allocations in catch-all path encoding

[madmax983]

💡 What:
Optimized encode_catch_all_param in autumn/src/paths.rs to append path segments directly into a pre-allocated String buffer instead of collecting an intermediate Vec<String> and then joining. Additionally, reused this optimized function in autumn/src/mcp.rs for build_request to handle MCP catch-all paths instead of duplicating the .collect::<Vec<_>>().join("/") pattern.

🎯 Why:
The .collect::<Vec<_>>().join("/") pattern requires multiple heap allocations: one for each segment string (during mapping) and one for the intermediate Vec holding them, which is immediately discarded after the .join("/") allocates the final string. Removing intermediate collections on string operations is a canonical zero-cost abstraction improvement.

📊 Impact:
Reduces heap allocations during the encoding of catch-all parameters. The exact number of allocations saved depends on the number of path segments, but it eliminates the Vec allocation entirely.

🔭 Measurement:
Run cargo bench if available for routing path encoding, or review the allocations in a memory profiler for MCP routing calls. Run cargo test -p autumn-web --lib to ensure no regressions in behavior.

---

PR created automatically by Jules for task 2922191217707296986 started by @madmax983

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!