feat: Wave 11 — birthdays tracker pack

resources/commands/birthdays/ (2 commands):
- birthdays.add  "запомни день рождения мама 15 марта" → memory key
  "birthday.мама" = "15.03". Accepts both DD.MM and "DD <month>"
  formats; recognises all 12 RU + 12 EN month names.
- birthdays.next "ближайший день рождения" → reads every "birthday.*"
  memory key, computes days-until each entry (with year wrap), speaks
  the nearest one in human form ("сегодня" / "завтра" / "через N дней").

Storage piggybacks on the existing long-term memory store, so
birthdays survive restart, sync to disk atomically, and don't need a
new persistence layer. Naming convention "birthday.<name>" keeps the
data discoverable in /memory GUI.

Pack count: 99 → 100 functional packs.
Tests: 140 rust, unchanged.

resources/commands/birthdays/command.toml

@@ -0,0 +1,50 @@
+# Birthday tracker — voice-add and check upcoming birthdays.
+# Storage uses `jarvis.memory.remember` with keys "birthday.<name>" so the
+# data lives in the same long-term memory store and survives across packs.
+#
+# Voice flow:
+#   "запомни день рождения мама 15 марта"
+#       → memory key "birthday.мама" = "15.03"
+#   "ближайший день рождения"  → reads all "birthday.*" keys + tells the next
+#   "день рождения мама"       → reads back what we know about Mom
+
+[[commands]]
+id = "birthdays.add"
+type = "lua"
+script = "add.lua"
+sandbox = "standard"
+timeout = 3000
+
+[commands.phrases]
+ru = [
+    "запомни день рождения",
+    "день рождения у",
+    "добавь день рождения",
+    "запиши день рождения",
+]
+en = [
+    "remember birthday",
+    "add birthday",
+    "save birthday",
+]
+
+
+[[commands]]
+id = "birthdays.next"
+type = "lua"
+script = "next.lua"
+sandbox = "standard"
+timeout = 3000
+
+[commands.phrases]
+ru = [
+    "ближайший день рождения",
+    "у кого скоро день рождения",
+    "кто следующий именинник",
+    "когда следующий день рождения",
+]
+en = [
+    "next birthday",
+    "whose birthday is next",
+    "upcoming birthdays",
+]