fix: add localhost to asset canister's CSP (#3476)

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 # UNRELEASED
 
+### fix: allow `http://localhost:*` as `connect-src` in the asset canister's CSP
+
+This will enable browsing the asset canister at `http://<canister-id>.localhost:<port>` in most browsers.
+
 ### fix: frontend code crashing when there is no canister ID
 
 ### feat: `dfx ledger top-up` also accepts canister names

src/dfx/assets/new_project_node_files/src/__project_name___frontend/assets/.ic-assets.json5

@@ -24,7 +24,7 @@
             //   See: https://github.com/WebAssembly/content-security-policy/blob/main/proposals/CSP.md.
             // - We added img-src data: because data: images are used often.
             // - frame-ancestors: none mitigates clickjacking attacks. See https://owasp.org/www-community/attacks/Clickjacking.
-            "Content-Security-Policy": "default-src 'self';script-src 'self' 'unsafe-eval';connect-src 'self' https://icp0.io https://*.icp0.io https://icp-api.io;img-src 'self' data:;style-src * 'unsafe-inline';style-src-elem * 'unsafe-inline';font-src *;object-src 'none';base-uri 'self';frame-ancestors 'none';form-action 'self';upgrade-insecure-requests;",
+            "Content-Security-Policy": "default-src 'self';script-src 'self' 'unsafe-eval';connect-src 'self' http://localhost:* https://icp0.io https://*.icp0.io https://icp-api.io;img-src 'self' data:;style-src * 'unsafe-inline';style-src-elem * 'unsafe-inline';font-src *;object-src 'none';base-uri 'self';frame-ancestors 'none';form-action 'self';upgrade-insecure-requests;",
 
             // Security: The permissions policy disables all features for security reasons. If your site needs such permissions, activate them.
             // To configure permissions go here https://www.permissionspolicy.com/

src/dfx/assets/new_project_node_files/src/__project_name___frontend/src/.ic-assets.json5

@@ -24,7 +24,7 @@
             //   See: https://github.com/WebAssembly/content-security-policy/blob/main/proposals/CSP.md.
             // - We added img-src data: because data: images are used often.
             // - frame-ancestors: none mitigates clickjacking attacks. See https://owasp.org/www-community/attacks/Clickjacking.
-            "Content-Security-Policy": "default-src 'self';script-src 'self' 'unsafe-eval';connect-src 'self' https://icp0.io https://*.icp0.io https://icp-api.io;img-src 'self' data:;style-src * 'unsafe-inline';style-src-elem * 'unsafe-inline';font-src *;object-src 'none';base-uri 'self';frame-ancestors 'none';form-action 'self';upgrade-insecure-requests;",
+            "Content-Security-Policy": "default-src 'self';script-src 'self' 'unsafe-eval';connect-src 'self' http://localhost:* https://icp0.io https://*.icp0.io https://icp-api.io;img-src 'self' data:;style-src * 'unsafe-inline';style-src-elem * 'unsafe-inline';font-src *;object-src 'none';base-uri 'self';frame-ancestors 'none';form-action 'self';upgrade-insecure-requests;",
 
             // Security: The permissions policy disables all features for security reasons. If your site needs such permissions, activate them.
             // To configure permissions go here https://www.permissionspolicy.com/