feat(webui): add SQL syntax highlighting to metric form editors

[mohamadyasser118]

As a follow-up to the web improvements and SQL display, I replaced plain OutlinedInput fields with react-simple-code-editor and prismjs for SQLs and InitSQL fields in the metric form. I see that this makes it easy to write SQLs.

Changes:

• SQLs field: full editor and syntax highlighting
• InitSQL field: same editor with smaller min-height
• I Used react-simple-code-editor (lightweight) over CodeMirror
  to avoid unnecessary bundle size increase
• Integrated with react-hook-form via Controller

SQLs Before:

SQLs After:

initSQL Before:

initSQL After:

AI & Automation Policy

• I am the human author and take full personal responsibility for every change in this PR.
• No AI or automated generative tool was used in any part of this PR OR I have disclosed all tool(s) below.
  Drafted and reviewed with the assistance Cluade Sonnet 4.6

Checklist

• Code compiles and existing tests pass locally.
• New or updated tests are included where applicable.
• Documentation is updated where applicable.