Feedback portal: navigation and field mapping issues resolved

A batch of small portal bugs that had been silently degrading the UX:

• Navigation between boards was occasionally rendering the previous board's posts on the new board's URL (stale state in the post list cache).
• A handful of field mappings between the database view and the UI components were inconsistent — same field had different names in different places, causing silent drops in some renders.

Both are normalised now. The portal renders the right data for the active route, every time.