## Summary
- Fixes periodic production crashes (undici ECONNREFUSED ::1) by
bounding server cache size/lifetime and hardening server HTTP client.
### Root cause
- React server cache (cache(...)) held axios responses indefinitely
across many parameter combinations, causing slow memory growth until the
Next.js app router worker was OOM-killed. The main server then failed
IPC to the worker (ECONNREFUSED ::1:<port>).
### Changes
- `app/lib/data.ts`: Replace unbounded cache(...) with unstable_cache
and explicit keys; TTLs: 60s for teams/detail/favorites/user, 300s for
meta (jobs/skills/accessories/raids/version).
- `app/lib/api-utils.ts`: Add shared Axios instance with 15s timeout and
keepAlive http/https agents; apply to GET/POST/PUT/DELETE helpers.
- `pages/api/preview/[shortcode].ts`: Remove duplicate handler to dedupe
route; retain the .tsx variant using `NEXT_PUBLIC_SIERO_API_URL`.
### Notes
- Build currently has pre-existing app/pages route duplication errors;
out of scope here but unrelated to this fix.
- Ensure `NEXT_PUBLIC_SIERO_API_URL` and `NEXT_PUBLIC_SIERO_OAUTH_URL`
are set on Railway.
### Risk/impact
- Low risk; behavior is unchanged aside from bounded caching and
resilient HTTP.
- Cache TTLs can be tuned later if needed.
### Test plan
- Verify saved/teams/user pages load and revalidate after TTL.
- Validate API routes still proxy correctly; timeouts occur after ~15s
for hung upstreams.
- Monitor memory over several days; expect stable usage without steady
growth.
## Component Refactors:
- Updated `CharacterHovercard` to improve over mastery and awakening
section logic.
- Refactored `CharacterModal` to streamline state management (rings,
awakening, perpetuity) and object preparation.
- Adjusted `CharacterUnit` for consistent over mastery handling.
- Simplified `AwakeningSelectWithInput` to use awakening slug values and
improve error handling.
- Updated `RingSelect` to refine ring value syncing and index logic.
- Modified `Party` and `PartyHead` to ensure consistent over mastery
processing and proper preview URL construction.
- Updated `WeaponModal` to align awakening value handling with the new
slug-based approach.
## Styling and Configuration:
- Improved grid layout and styling in the `WeaponRep` SCSS module.
- Updated `next.config.js` rewrite rules to support new preview and
character routes.
- Added a new API endpoint (`pages/api/preview/[shortcode].tsx`) for
fetching party preview images.
## Type Definitions:
- Refined types in `types/GridCharacter.d.ts` and `types/index.d.ts` to
reflect updated structures for rings, over mastery, and awakening.
* Writes redirect for preview images so we're not embedding the API URL
in user-facing pages
* Adds the NextJs API page that actually serves the image
* Use a more straightforward URL construction method
* Add the og:image:width and og:image:height
