feat: live memory materialization — nodes spawn in 3D graph in real-time

When memories are created, promoted, deleted, or dreamed via MCP tools,
the 3D graph now shows spectacular live animations:

- Rainbow particle burst + elastic scale-up on MemoryCreated
- Ripple wave cascading to nearby nodes
- Green pulse + node growth on MemoryPromoted
- Implosion + dissolution on MemoryDeleted
- Edge growth animation on ConnectionDiscovered
- Purple cascade on DreamStarted/DreamProgress/DreamCompleted
- FIFO eviction at 50 live nodes to guard performance

Also: graph center defaults to most-connected node, legacy HTML
redirects to SvelteKit dashboard, CSS height chain fix in layout.

Testing: 150 unit tests (vitest), 11 e2e tests (Playwright with
MCP Streamable HTTP client), 22 proof screenshots.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

crates/vestige-core/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "vestige-core"
-version = "2.0.2"
+version = "2.0.3"
 edition = "2024"
 rust-version = "1.91"
 authors = ["Vestige Team"]

crates/vestige-core/src/storage/sqlite.rs

@@ -3532,6 +3532,21 @@ impl Storage {
         Ok(result)
     }
 
+    /// Get the memory with the most connections (best center node for graph visualization)
+    pub fn get_most_connected_memory(&self) -> Result<Option<String>> {
+        let reader = self.reader.lock()
+            .map_err(|_| StorageError::Init("Reader lock poisoned".into()))?;
+        let mut stmt = reader.prepare(
+            "SELECT id, COUNT(*) as cnt FROM (
+                SELECT source_id as id FROM memory_connections
+                UNION ALL
+                SELECT target_id as id FROM memory_connections
+            ) GROUP BY id ORDER BY cnt DESC LIMIT 1"
+        )?;
+        let result = stmt.query_row([], |row| row.get::<_, String>(0)).optional()?;
+        Ok(result)
+    }
+
     /// Get memories with their connection data for graph visualization
     pub fn get_memory_subgraph(&self, center_id: &str, depth: u32, max_nodes: usize) -> Result<(Vec<KnowledgeNode>, Vec<ConnectionRecord>)> {
         let mut visited_ids: std::collections::HashSet<String> = std::collections::HashSet::new();