Add redirect for /project/xyz to /instance/xyz

[knolleary]

Fixes #3799

The nr-launcher includes a link to the FF application in the format /project/:id. At some point, that has started to 404. This adds a redirect in place so it gets to the right place.

I'll raise a separate PR on nr-launcher to use the right url to start with. already done via FlowFuse/nr-launcher#229

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 41.70%. Comparing base (426379c) to head (cf372a0).
Report is 3 commits behind head on main.

❗ Current head cf372a0 differs from pull request most recent head 165d800. Consider uploading reports for the commit 165d800 to get more accurate results

Files	Patch %	Lines
frontend/src/pages/instance/routes.js	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3808      +/-   ##
==========================================
- Coverage   41.71%   41.70%   -0.02%     
==========================================
  Files         650      650              
  Lines       24809    24803       -6     
  Branches     6091     6084       -7     
==========================================
- Hits        10350    10345       -5     
+ Misses      14459    14458       -1     

Flag	Coverage Δ
backend	79.14% <ø> (+<0.01%)	⬆️
frontend	1.88% <0.00%> (+<0.01%)	⬆️

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