ci(build): keep Angular's disk cache in CI so the cache step has something to save

The first run of these cache steps showed the npm entry saving (234 MB) and the
Angular one reporting 'Path Validation Error: Path(s) specified in the action
for caching do(es) not exist'. Angular keeps its persistent cache in memory
when CI is set, so no .angular/cache directory existed to upload; the disk
cache is only used outside CI by default.

client/angular.json now sets cli.cache.environment to "all", which is the
supported switch for that. Verified locally with CI=true: after removing
.angular/cache, a build recreates it (396 MB).

.gitea/workflows/build.yaml

@@ -105,6 +105,11 @@ jobs:
         # cache is content-addressed and drops its own stale entries, so a
         # lockfile-keyed entry stays correct.
         #
+        # Angular keeps that cache in memory when CI is set, so client/
+        # angular.json sets cli.cache.environment to "all" - without it this
+        # step has nothing to save ("Path Validation Error: Path(s) specified
+        # in the action for caching do(es) not exist").
+        #
         # actions/cache does not save a second entry for a key that already
         # exists, so this cache is refreshed only when client/package-lock.json
         # changes. The win therefore decays as the app moves away from the

client/angular.json

@@ -1,7 +1,10 @@
 {
   "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
   "cli": {
-    "analytics": false
+    "analytics": false,
+    "cache": {
+      "environment": "all"
+    }
   },
   "version": 1,
   "newProjectRoot": "projects",