Convert collector seed mechanism from JSON to YAML

- Replace JSON seed files with YAML format for better readability
- Auto-detect YAML primitive types (number, boolean, string) from values
- Add automatic seed import on collector startup
- Split lat/lon into separate tags instead of combined coordinate string
- Add PyYAML dependency and types-PyYAML for type checking
- Update example/seed and contrib/seed/ipnet with clean YAML format
- Update tests to verify YAML primitive type detection

example/seed/members.json

@@ -1,10 +0,0 @@
-{
-  "members": [
-    {
-      "name": "Example Member",
-      "callsign": "N0CALL",
-      "role": "Network Operator",
-      "description": "Example member entry"
-    }
-  ]
-}

example/seed/members.yaml

@@ -0,0 +1,6 @@
+# Example members seed file
+members:
+  - name: Example Member
+    callsign: N0CALL
+    role: Network Operator
+    description: Example member entry

example/seed/node_tags.json

@@ -1,16 +0,0 @@
-{
-  "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef": {
-    "friendly_name": "Gateway Node",
-    "location": {"value": "37.7749,-122.4194", "type": "coordinate"},
-    "lat": {"value": "37.7749", "type": "number"},
-    "lon": {"value": "-122.4194", "type": "number"},
-    "role": "gateway"
-  },
-  "fedcba9876543210fedcba9876543210fedcba9876543210fedcba9876543210": {
-    "friendly_name": "Oakland Repeater",
-    "location": {"value": "37.8044,-122.2712", "type": "coordinate"},
-    "lat": {"value": "37.8044", "type": "number"},
-    "lon": {"value": "-122.2712", "type": "number"},
-    "altitude": {"value": "150", "type": "number"}
-  }
-}

example/seed/node_tags.yaml

@@ -0,0 +1,29 @@
+# Example node tags seed file
+# Each key is a 64-character hex public key
+#
+# Tag values can be:
+# - YAML primitives (auto-detected type):
+#     friendly_name: Gateway Node  # string
+#     elevation: 150               # number
+#     is_online: true              # boolean
+#
+# - Explicit type (for special types like coordinate):
+#     location:
+#       value: "37.7749,-122.4194"
+#       type: coordinate
+#
+# Supported types: string, number, boolean, coordinate
+
+0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef:
+  friendly_name: Gateway Node
+  role: gateway
+  lat: 37.7749
+  lon: -122.4194
+  is_online: true
+
+fedcba9876543210fedcba9876543210fedcba9876543210fedcba9876543210:
+  friendly_name: Oakland Repeater
+  lat: 37.8044
+  lon: -122.2712
+  altitude: 150
+  is_online: false