feat: implement v0.6.0 mutation engine and db_type runtime selection

frontend/heartbeat.js

@@ -1,10 +1,21 @@
-import init, { generate_keypair, sign_message, compute_next_hash, run_program } from './pkg/chronoseal_wasm.js';
+import init, {
+    generate_keypair,
+    sign_message,
+    compute_next_hash,
+    run_program,
+    init_gene_state,
+    preview_gene_commitment,
+    commit_gene_preview,
+    discard_gene_preview
+} from './pkg/chronoseal_wasm.js';
 import { collectEntropy } from './entropy.js';
 import { sendRequest } from './transport.js';
 
 let session, prevHash, currentSalt, opcodesB64, lastTime;
 let minInterval = 12000;
 let maxInterval = 25000;
+let pendingMutationStep = 0;
+let pendingMutationOrderB64 = '';
 
 export async function initHeartbeat() {
     await init();
@@ -16,6 +27,11 @@ export async function initHeartbeat() {
     opcodesB64 = initResp.opcodes_b64;
     minInterval = initResp.heartbeat_min_interval_ms || 12000;
     maxInterval = initResp.heartbeat_max_interval_ms || 25000;
+    if (!init_gene_state(initResp.gene_size || 512)) {
+        throw new Error('Failed to initialize gene state');
+    }
+    pendingMutationStep = initResp.mutation_step;
+    pendingMutationOrderB64 = initResp.mutation_order_b64;
     lastTime = performance.now();
     scheduleNext();
 }
@@ -40,6 +56,10 @@ async function sendHeartbeat() {
         const timestamp = Date.now();
         const entropyData = { events: events.map(e => ({ x: e.x, y: e.y, t: e.t })) };
         const entropyJson = JSON.stringify(entropyData);
+        const geneCommitment = preview_gene_commitment(pendingMutationOrderB64);
+        if (!geneCommitment) {
+            throw new Error('Unable to compute mutation commitment');
+        }
 
         const signable = {
             sessionId: session,
@@ -47,11 +67,14 @@ async function sendHeartbeat() {
             timestamp: timestamp,
             entropyData: entropyData,
             stackState: JSON.parse(stackState),
-            fingerprint: fingerprint
+            fingerprint: fingerprint,
+            mutationStep: pendingMutationStep,
+            geneCommitment: geneCommitment
         };
         const msg = JSON.stringify(signable, Object.keys(signable).sort());
         const sig = sign_message(msg);
         if (!sig) {
+            discard_gene_preview();
             console.error('Keypair not initialised — skipping heartbeat');
             return;
         }
@@ -62,22 +85,32 @@ async function sendHeartbeat() {
             entropy_data: entropyData,
             stack_state: JSON.parse(stackState),
             fingerprint,
+            mutation_step: pendingMutationStep,
+            gene_commitment: geneCommitment,
             signature: sig
         });
 
-        if (resp.next_salt) {
+        if (resp.next_salt && resp.next_mutation_step && resp.next_mutation_order_b64) {
+            if (!commit_gene_preview()) {
+                discard_gene_preview();
+                throw new Error('Failed to commit local mutation preview');
+            }
             // IMPORTANT: capture the salt that was active when this heartbeat was sent.
             // The server computes new_hash = H(prev, ts, entropy, stack, OLD_salt) and stores it,
             // then rotates to next_salt.  We must mirror that using the same old salt, then rotate.
             const sentSalt = currentSalt;
             currentSalt = resp.next_salt;
             prevHash = compute_next_hash(prevHash, timestamp, entropyJson, stackState, sentSalt);
+            pendingMutationStep = resp.next_mutation_step;
+            pendingMutationOrderB64 = resp.next_mutation_order_b64;
         } else {
+            discard_gene_preview();
             console.warn('Heartbeat rejected');
         }
     } catch (e) {
+        discard_gene_preview();
         console.error(e);
     } finally {
         scheduleNext();
     }
-}
+}