Add homeassistant skill in unpacked format

- Add complete homeassistant skill source to skills/ directory
- Includes all scripts, references, and automation templates
- Matches format of other skills in repository

skills/homeassistant/assets/automation_templates/presence_detection.yaml

@@ -0,0 +1,57 @@
+automation:
+  - alias: "Presence-Based Automation"
+    id: presence_detection_template
+    description: "React to people arriving or leaving home"
+
+    trigger:
+      - trigger: state
+        entity_id: person.REPLACE_WITH_PERSON
+        from: "not_home"
+        to: "home"
+        id: arriving
+
+      - trigger: state
+        entity_id: person.REPLACE_WITH_PERSON
+        from: "home"
+        to: "not_home"
+        id: leaving
+
+    action:
+      - choose:
+          # When arriving home
+          - conditions:
+              - condition: trigger
+                id: arriving
+            sequence:
+              - action: light.turn_on
+                target:
+                  area_id: entrance
+
+              - action: climate.set_temperature
+                target:
+                  entity_id: climate.REPLACE_WITH_CLIMATE_DEVICE
+                data:
+                  temperature: 22
+
+              - action: notify.mobile_app_REPLACE_WITH_DEVICE
+                data:
+                  message: "Welcome home!"
+
+          # When leaving home
+          - conditions:
+              - condition: trigger
+                id: leaving
+            sequence:
+              - action: light.turn_off
+                target:
+                  entity_id: all
+
+              - action: climate.set_hvac_mode
+                target:
+                  entity_id: climate.REPLACE_WITH_CLIMATE_DEVICE
+                data:
+                  hvac_mode: "off"
+
+              - action: notify.mobile_app_REPLACE_WITH_DEVICE
+                data:
+                  message: "Goodbye! Home secured."