Add multi-community theme folder structure

[victoria-lo]

We’d like to make this tool more community-agnostic and easily reusable by other tech groups (for example: open source meetups, developer community organisations, hackathon groups, etc). Right now it is branded and structured around ragTechDev, but with a few adjustments it could serve a wider audience.

Goals:

• Allow other tech communities to add their own brand (names, logos, colours) without needing deep code changes.
• Provide a clear onboarding path for new communities to fork/customise the project.
• Make configuration of templates (templates for social posts, event banners, etc) more flexible so communities can adapt text/layout/logo easily.
• Keep the core functionality (canvas export, platform sizes, etc) intact, but separate “branding assets” from core logic.

Sub-issues:

We’d like to make this tool more community-agnostic and easily reusable by other tech groups (for example: open source meetups, developer community organisations, hackathon groups, etc). Right now it is branded and structured around ragTechDev, but with a few adjustments it could serve a wider audience.

Goals:

• Allow other tech communities to add their own brand (names, logos, colours) without needing deep code changes.
• Provide a clear onboarding path for new communities to fork/customise the project.
• Make configuration of templates (templates for social posts, event banners, etc) more flexible so communities can adapt text/layout/logo easily.
• Keep the core functionality (canvas export, platform sizes, etc) intact, but separate “branding assets” from core logic.

Sub-issues:

• Add community configuration system #1
• Refactor template components to use config #2
• Add multi-community theme folder structure #3
• Add theme selector #4
• Update README and documentation #5
• Add example community preset #6
• Add automated test coverage #7

#3 Add multi-community theme folder structure

Goal: Support multiple community themes stored separately.

Description:
Create a structure such as /themes/{communityName}/ to store assets and config per community.
The app should automatically load assets from the chosen theme folder.

Acceptance criteria:

• Folder structure supports multiple communities.
• Each theme folder includes its own config, logos, and favicon.
• Default to /themes/ragTechDev/ if no community specified.
• Proper error message if theme folder missing required files.

Dependencies: #1