Fix Supabase configuration, table naming inconsistencies, and routing issues

[its-nott-me]

Summary

This PR addresses several early-stage issues related to Supabase setup, database schema consistency, storage uploads, and routing behavior.

The changes aim to improve reliability, portability, and deployment readiness without altering existing features.

Changes Included

• Standardized database table names to lowercase (posts, communities, comments, votes) across the codebase and README to avoid schema cache and casing issues
• Fixed Supabase client configuration to use environment variables instead of a hardcoded project URL
• Ensured user_id is always set when creating posts to satisfy NOT NULL constraints
• Sanitized post titles used in Supabase Storage filenames to prevent upload collisions (e.g. # being treated as a fragment)
• Aligned React Router navigation with Vite base path:
  • Added router basename support
  • Replaced hard redirects (window.location.href) with router navigation

Why These Changes

• Prevents Supabase runtime errors caused by case-sensitive table names
• Improves security and portability of Supabase configuration
• Fixes storage upload failures for posts with special characters in titles
• Ensures routing works correctly when deployed under a subpath (e.g. GitHub Pages)

Notes

• Changes are backward-compatible
• Commits are intentionally kept small and focused for easier review
• Happy to split or adjust commits if preferred by maintainers

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[TiwariDivya25]

Thanks for the PR. I’m reviewing the table naming changes to ensure they align with the current Supabase schema. Once confirmed, I’ll proceed with merging.