Fix ETS table init, send failure handling, and deployment cleanup

- Initialize :aprsme ETS table in application.ex with message_number
  counter; was missing, causing crash in Is.send_message/1
- Trigger reconnect on gen_tcp.send failure instead of leaking the
  dead socket with active timers
- Remove cluster-only env vars from deployment (POD_IP, POD_NAME,
  POD_NAMESPACE, RELEASE_DISTRIBUTION, RELEASE_NODE) since
  CLUSTER_ENABLED=false
- Remove redundant APRS_PASSCODE secret ref now that APRS_PASSWORD
  is set as plaintext

k8s/deployment.yaml

@@ -108,22 +108,6 @@ spec:
                   - -c
                   - sleep 20
           env:
-            - name: POD_IP
-              valueFrom:
-                fieldRef:
-                  fieldPath: status.podIP
-            - name: POD_NAME
-              valueFrom:
-                fieldRef:
-                  fieldPath: metadata.name
-            - name: POD_NAMESPACE
-              valueFrom:
-                fieldRef:
-                  fieldPath: metadata.namespace
-            - name: RELEASE_DISTRIBUTION
-              value: "name"
-            - name: RELEASE_NODE
-              value: "aprsme@$(POD_IP)"
             - name: CLUSTER_ENABLED
               value: "false"
             - name: PORT
@@ -154,11 +138,6 @@ spec:
                 secretKeyRef:
                   name: aprs-secrets
                   key: SECRET_KEY_BASE
-            - name: APRS_PASSCODE
-              valueFrom:
-                secretKeyRef:
-                  name: aprs-secrets
-                  key: APRS_PASSCODE
           envFrom:
             - secretRef:
                 name: aprs-db

lib/aprsme/application.ex

@@ -251,6 +251,8 @@ defmodule Aprsme.Application do
     :ets.new(:query_cache, [:set, :public, :named_table, read_concurrency: true])
     :ets.new(:device_cache, [:set, :public, :named_table, read_concurrency: true])
     :ets.new(:symbol_cache, [:set, :public, :named_table, read_concurrency: true])
+    :ets.new(:aprsme, [:set, :public, :named_table, write_concurrency: true])
+    :ets.insert(:aprsme, {:message_number, 0})
 
     [
       # ETS-based rate limiter

lib/aprsme/is/is.ex

@@ -244,7 +244,11 @@ defmodule Aprsme.Is do
 
           error ->
             Logger.error("Failed to send message to APRS-IS: #{inspect(error)}")
-            {:reply, {:error, error}, state}
+            if state.timer, do: Process.cancel_timer(state.timer)
+            if state.keepalive_timer, do: Process.cancel_timer(state.keepalive_timer)
+            :gen_tcp.close(socket)
+            schedule_reconnect(5000)
+            {:reply, {:error, error}, %{state | socket: nil, timer: nil, keepalive_timer: nil}}
         end
     end
   end