feat: refine web analytics and history views

arr_web/company_jobs.py

@@ -133,6 +133,9 @@ class CompanyReportCoordinator(Protocol):
     ) -> tuple[List[Dict[str, Any]], int]:
         ...
 
+    def list_month_counts(self) -> List[Dict[str, Any]]:
+        ...
+
     def get_job(self, job_id: str) -> Dict[str, Any]:
         ...
 
@@ -160,6 +163,9 @@ class UnavailableCompanyReportCoordinator:
     ) -> tuple[List[Dict[str, Any]], int]:
         raise self._unavailable()
 
+    def list_month_counts(self) -> List[Dict[str, Any]]:
+        return []
+
     def get_job(self, job_id: str) -> Dict[str, Any]:
         raise self._unavailable()
 
@@ -292,6 +298,23 @@ class PersistentCompanyReportCoordinator:
             page = states[offset : offset + limit]
             return [self._public_locked(state) for state in page], total
 
+    def list_month_counts(self) -> List[Dict[str, Any]]:
+        with self._condition:
+            counts: Dict[str, int] = {}
+            for state in self._states_locked():
+                month_key = state.get("report_month")
+                if not isinstance(month_key, str):
+                    continue
+                try:
+                    validate_month(month_key)
+                except PortalError:
+                    continue
+                counts[month_key] = counts.get(month_key, 0) + 1
+            return [
+                {"month_key": month_key, "company_count": counts[month_key]}
+                for month_key in sorted(counts, reverse=True)
+            ]
+
     def get_job(self, job_id: str) -> Dict[str, Any]:
         with self._condition:
             return self._public_locked(self._read_locked(job_id))