fix(logging): redirect request validation warnings & errors to in-app console (#906, #587)

[avisikta17pal]

• Add GET-with-body validation warning to terminal console
• Add JSON validation error logging for invalid request bodies
• Add empty URL validation error logging
• Add request validation completion info logging
• Replace transient UI notifications with persistent terminal logs
• Maintain consistent logging format with categories and tags
• Fix duplicate terminal reference after autofix

Resolves #906: Migrate to in-app logging console
Resolves #587: Add a Global status bar in API Dash

PR Description

This PR migrates all transient request validation notifications to the persistent in-app terminal console.
It ensures that all validation messages — including GET-with-body warnings, JSON validation errors, and empty URL alerts — are logged with proper severity levels (warn, error, info, debug) and categorized under validation.

This improves developer visibility, allows filtering by tags, and aligns with the project’s logging architecture.

Related Issues

• Closes Migrate to in-app logging console #906
• Closes Add a Global status bar in API Dash #587

Checklist

• I have gone through the contributing guide
• I have updated my branch and synced it with project main branch before making this PR
• I am using the latest Flutter stable branch (run flutter upgrade and verify)
• I have run the tests (flutter test) and all tests are passing

Added/updated tests?

• Yes
• No, and this is why: validation changes rely on existing console logging infrastructure, tested manually via UI and terminal logs

OS on which you have developed and tested the feature?

• Windows
• macOS
• Linux

[avisikta17pal]

✅ Implementation verified.

The fix correctly redirects all validation warnings and errors to the in-app console and matches the requirements discussed in issue #906.
Logs appear persistently in the terminal console with correct levels (warn/error/info/debug) and categorization under validation.

Tested on:

• Windows (Flutter stable channel)
• Verified for GET-with-body, invalid JSON, empty URL, and successful validation flows.