feat: add Tag, TagSuggestion, Connection models and extend Member schema

Adds three new Mongoose models for the community connections feature. Extends
Member with craftTags, communityConnections block, privacy fields for both,
and a connectionRequests notification preference.

server/models/connection.js

@@ -0,0 +1,22 @@
+import mongoose from 'mongoose'
+
+const connectionSchema = new mongoose.Schema({
+  initiator: { type: mongoose.Schema.Types.ObjectId, ref: 'Member', required: true },
+  recipient: { type: mongoose.Schema.Types.ObjectId, ref: 'Member', required: true },
+  status: { type: String, enum: ['pending', 'confirmed'], default: 'pending' },
+  matchingTags: [
+    {
+      tagSlug: String,
+      initiatorState: String,
+      recipientState: String,
+    },
+  ],
+  hiddenBy: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Member' }],
+  createdAt: { type: Date, default: Date.now },
+  confirmedAt: Date,
+})
+
+connectionSchema.index({ initiator: 1, recipient: 1 }, { unique: true })
+connectionSchema.index({ recipient: 1, status: 1 })
+
+export default mongoose.models.Connection || mongoose.model('Connection', connectionSchema)