feat: HNSW index, consolidation engine, Kotlin/TS/Go bindings, SQLite migration connector

- vector.rs: replace flat O(n) scan with instant-distance HNSW for stores
  >= 100 nodes; flat scan retained as fallback for small graphs; dirty-flag
  persistence in sled triggers index rebuild only when nodes are added

- consolidation.rs: Episodic → Semantic promotion based on activation_count
  and salience_floor thresholds; global decay pass after each cycle;
  ConsolidationConfig + ConsolidationReport types; 8 tests

- migration.rs: reads Neuron SQLite (memory_nodes, knowledge_entries,
  graph_edges) and writes to Engram sled; placeholder unit-vector embeddings
  with TODO for ONNX; 5 tests including full in-memory DB roundtrip

- crates/engram-migrate: CLI binary (engram-migrate --sqlite / --output)

- crates/engram-jni: JNI cdylib exposing open/close/put_node/get_node/
  activate/search_embedding/touch/decay/node_count/edge_count via
  Java_ai_neuron_engram_EngramDb_* entry points; 6 tests

- bindings/kotlin: EngramDb.kt (AutoCloseable JNI wrapper), EngramNode,
  EngramEdge, ActivatedNode, EngramTypes; build.gradle.kts; settings.gradle.kts

- bindings/typescript: engram-wasm crate (wasm-bindgen, serde-wasm-bindgen);
  WasmEngramDb with in-memory backend (sled not available in WASM);
  TypeScript wrapper (index.ts, types.ts, package.json, tsconfig.json)

- bindings/go: engram.go (CGo wrapper), engram.h (C header), engram_test.go
  (4 tests covering open/close/put_node/get_node/node_count/decay); go.mod

- engram-core: wasm feature gate for in-memory backend; mem_storage.rs;
  activation.activate_mem for WASM path; Node::with_id helper;
  salience.rs doctest fixed (text block)

- examples/basic.rs: consolidation section added
- examples/migrate.rs: migration API demonstration

Build: cargo build --workspace -- zero warnings, zero errors
Tests: 38 pass (25 engram-core + 7 engram-ffi + 6 engram-jni)

crates/engram-migrate/src/main.rs

@@ -0,0 +1,105 @@
+/// engram-migrate — import a Neuron SQLite database into an Engram sled store.
+///
+/// Usage:
+///   engram-migrate --sqlite ~/.neuron/neuron.db --output ~/.engram/neuron
+///
+/// The tool reads memory_nodes, knowledge_entries, and graph_edges from the
+/// Neuron SQLite database and writes them to a new Engram sled store.
+///
+/// Embeddings are placeholder random unit vectors (dimension 384 by default).
+/// Re-run with a real embedding model once the ONNX engine is available.
+use engram_core::migration::{migrate_from_neuron, MigrationConfig};
+use std::path::PathBuf;
+use std::process;
+
+fn main() {
+    let args: Vec<String> = std::env::args().collect();
+
+    if args.len() < 5 {
+        eprintln!("Usage: engram-migrate --sqlite <path> --output <path>");
+        eprintln!("  --sqlite   Path to the Neuron SQLite database (e.g. ~/.neuron/neuron.db)");
+        eprintln!("  --output   Path for the new Engram sled store (e.g. ~/.engram/neuron)");
+        process::exit(1);
+    }
+
+    let mut sqlite_path: Option<PathBuf> = None;
+    let mut output_path: Option<PathBuf> = None;
+    let mut embedding_dim: usize = 384;
+
+    let mut i = 1;
+    while i < args.len() {
+        match args[i].as_str() {
+            "--sqlite" => {
+                i += 1;
+                sqlite_path = Some(PathBuf::from(&args[i]));
+            }
+            "--output" => {
+                i += 1;
+                output_path = Some(PathBuf::from(&args[i]));
+            }
+            "--embedding-dim" => {
+                i += 1;
+                embedding_dim = args[i].parse().unwrap_or(384);
+            }
+            _ => {
+                eprintln!("Unknown argument: {}", args[i]);
+                process::exit(1);
+            }
+        }
+        i += 1;
+    }
+
+    let sqlite_path = match sqlite_path {
+        Some(p) => p,
+        None => {
+            eprintln!("Missing --sqlite argument");
+            process::exit(1);
+        }
+    };
+
+    let output_path = match output_path {
+        Some(p) => p,
+        None => {
+            eprintln!("Missing --output argument");
+            process::exit(1);
+        }
+    };
+
+    if !sqlite_path.exists() {
+        eprintln!("SQLite file not found: {}", sqlite_path.display());
+        process::exit(1);
+    }
+
+    println!("Migrating Neuron database...");
+    println!("  Source:  {}", sqlite_path.display());
+    println!("  Output:  {}", output_path.display());
+    println!("  Embedding dim: {}", embedding_dim);
+    println!();
+
+    let config = MigrationConfig {
+        sqlite_path,
+        engram_path: output_path,
+        embedding_dim,
+    };
+
+    match migrate_from_neuron(&config) {
+        Ok(report) => {
+            println!("Migration complete.");
+            println!("  Memories migrated:   {}", report.memories_migrated);
+            println!("  Knowledge migrated:  {}", report.knowledge_migrated);
+            println!("  Edges created:       {}", report.edges_created);
+
+            if !report.errors.is_empty() {
+                println!();
+                println!("Non-fatal errors ({}):", report.errors.len());
+                for e in &report.errors {
+                    println!("  - {}", e);
+                }
+            }
+        }
+        Err(e) => {
+            eprintln!("Migration failed: {}", e);
+            process::exit(1);
+        }
+    }
+}