Update CV release to v1.0.3, add X-Clacks-Overhead header (#176)

## Summary
- Update CV release URL from v1.0.2 to v1.0.3
- Add `X-Clacks-Overhead: GNU Terry Pratchett` header to both `docs.eblu.me` and `cv.eblu.me` server blocks in the Fly.io proxy nginx config

## Deployment and Testing
- [ ] Sync CV app: `argocd app sync cv`
- [ ] Verify CV is serving v1.0.3 content
- [ ] Deploy fly proxy (workflow or `mise run fly-deploy`)
- [ ] Verify header: `curl -sI https://docs.eblu.me | grep -i clacks`
- [ ] Verify header: `curl -sI https://cv.eblu.me | grep -i clacks`

Reviewed-on: https://forge.ops.eblu.me/eblume/blumeops/pulls/176

docs/changelog.d/cv-v1.0.3-and-clacks.feature.md

@@ -0,0 +1 @@
+Update CV release to v1.0.3.

docs/changelog.d/cv-v1.0.3-and-clacks.misc.md

@@ -0,0 +1 @@
+Add X-Clacks-Overhead header to public proxy for cv and docs: GNU Terry Pratchett.

docs/how-to/expose-service-publicly.md

@@ -229,6 +229,7 @@ http {
             proxy_ignore_headers Cache-Control Set-Cookie;
 
             add_header X-Cache-Status $upstream_cache_status;
+            add_header X-Clacks-Overhead "GNU Terry Pratchett" always;
         }
     }
 
@@ -454,6 +455,7 @@ server {
         proxy_ignore_headers Cache-Control Set-Cookie;
 
         add_header X-Cache-Status $upstream_cache_status;
+        add_header X-Clacks-Overhead "GNU Terry Pratchett" always;
     }
 }
 ```
@@ -503,6 +505,7 @@ server {
         proxy_cache_key $host$uri;
 
         add_header X-Cache-Status $upstream_cache_status;
+        add_header X-Clacks-Overhead "GNU Terry Pratchett" always;
     }
 }
 ```