fix(ci): resolve HTTP/2 framing errors from Attic cache

Disable nginx proxy buffering and enforce HTTP/1.1 upstream for
cache.zx.dev to prevent stream errors when downloading large NARs over
HTTP/2. Also add --fallback to attic-client install in CI.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: stackptr

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
           extra-trusted-public-keys = main:mu0jkxdJTGWC3djDSEQb3rvZgqlhA8WVMulcTo5IW6c=
     - name: Configure Attic cache
       run: |
-        nix profile install --inputs-from . attic#attic-client
+        nix profile install --inputs-from . attic#attic-client --fallback
         attic login rc https://cache.zx.dev ${{ secrets.ATTIC_TOKEN }}
         attic use rc:main
     - name: Build system configuration

.github/workflows/deploy.yml

@@ -40,7 +40,7 @@ jobs:
 
       - name: Configure Attic cache
         run: |
-          nix profile install --inputs-from . attic#attic-client
+          nix profile install --inputs-from . attic#attic-client --fallback
           attic login rc https://cache.zx.dev ${{ secrets.ATTIC_TOKEN }}
           attic use rc:main
 

hosts/spore/services/web/default.nix

@@ -95,6 +95,8 @@
           extraConfig = ''
             client_max_body_size 0;
             proxy_read_timeout 300;
+            proxy_buffering off;
+            proxy_http_version 1.1;
           '';
         };
       };