Promote calendar snapshot to v1.5.5 release

The calendar local-time and AI airport-read fixes are a numbered product release rather than a temporary snapshot, so the changelog and package/version metadata now use 1.5.5 consistently.

Constraint: Existing snapshot tag was already pushed before the numbered release correction

Rejected: Keep snapshot label in changelog | user clarified this should be the 1.5.5 version

Confidence: high

Scope-risk: narrow

Tested: Reviewed git diff for CHANGELOG, VERSION, frontend package metadata

Not-tested: No runtime tests; metadata-only version correction

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "polyweather-frontend",
-  "version": "1.5.4",
+  "version": "1.5.5",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "polyweather-frontend",
-      "version": "1.5.4",
+      "version": "1.5.5",
       "dependencies": {
         "@radix-ui/react-slot": "^1.1.2",
         "@supabase/ssr": "^0.5.2",