Optimize string formatting to reduce allocations

[Copilot]

Identified and fixed inefficient string handling patterns that cause unnecessary heap allocations in hot paths (progress rendering, benchmarking, LSP operations).

Changes

• Replace push_str(&format!(...)) with write! macro - Eliminates intermediate String allocation per call

  // Before: allocates temporary String
  text.push_str(&format!("{}", value));
  
  // After: writes directly
  let _ = write!(text, "{}", value);

• Remove redundant .to_string() after .join() - .join() already returns String

• Use into_iter() instead of .iter().map(|s| s.to_string()) - Moves owned strings rather than cloning

• Optimize hex fingerprint formatting - Replaced N allocations with single pre-sized buffer using write! in loop

• Eliminate intermediate Vec in string building - Changed .collect::<Vec<_>>().join("\n") to direct string building with conditional newlines

Impact

Most significant in:

• cli/lsp/language_server.rs - Status page generation (68 net line change)
• cli/tools/bench/mitata.rs - Benchmark output formatting
• ext/node/ops/crypto/x509.rs - Certificate fingerprint computation

10 files modified. All changes maintain existing APIs and behavior.

Original prompt

Identify and suggest improvements to slow or inefficient code

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}