Stop caching index.html so deploys take effect immediately

[skearnes]

Split out from #201.

nginx served index.html with ETag/Last-Modified but no Cache-Control, so browsers heuristically cached it and kept loading the previous build's hashed bundle until a manual hard refresh (this is why a freshly deployed UI change didn't appear without one).

• index.html → Cache-Control: no-cache (always revalidate; cheap 304s via the existing ETag).
• /assets/ (Vite content-hashed, immutable) → Cache-Control: public, max-age=31536000, immutable.

New deploys are picked up on the next normal navigation, with no stale-asset risk.

Testing

• nginx -t against the updated config: syntax OK.

🤖 Generated with Claude Code

Greptile Summary

This PR fixes browser heuristic caching of index.html that prevented freshly deployed UI changes from appearing without a hard refresh. A map directive keyed on $uri drives a single server-level add_header Cache-Control $cache_control, routing Vite content-hashed assets to public, max-age=31536000, immutable and the SPA entry point to no-cache.

• Placing the directive at the server block rather than duplicating it in every location block correctly avoids the add_header inheritance pitfall flagged on the previous attempt.
• Empty string values in the map (default \"\") cause nginx to suppress the header entirely for proxied API/editor responses, which is the correct behavior.
• The try_files $uri $uri/ /index.html fallback and the index index.html resolution both perform an internal redirect that updates $uri to /index.html before the response-filter phase, so the no-cache policy is applied to all SPA routes—not just literal /index.html requests.

Confidence Score: 5/5

Safe to merge — the change is a targeted nginx caching fix with no logic changes to the application code.

The map + server-level add_header approach is correct: empty values suppress the header for proxied routes, the /index.html pattern covers all SPA routes served via try_files/index rewrites, and assets get a proper immutable policy. No correctness issues found.

No files require special attention.

Important Files Changed

Filename	Overview
ord_interface/nginx.conf	Adds a map-based Cache-Control policy: no-cache for index.html, immutable for /assets/, and no header for API/editor routes; header is set once at the server level to avoid add_header inheritance surprises.

_{Reviews (2): Last reviewed commit: "Set SPA cache headers via a server-level..." | Re-trigger Greptile}