test: use strict equality for schema snapshot comparisons

A test whose job is catching subtle JSON-serializer drift should not use
loose comparison - deepEqual would pass a string 1 against a numeric 1.
Also documents the zod/v4 isSchemaOptional() quirk on bare .default()
at the call site rather than only in a planning doc.

src/vector/self-improvement.ts

@@ -713,6 +713,10 @@ activity tracking token (\`pact_\`) minted. Visible on the Foundation dashboard.
       mnemonic: z.string().describe("15 or 24-word BIP39 mnemonic for the wallet"),
       agentDid: z.string().describe("Agent DID (hex)"),
       proposalTxHash: z.string().describe("TX hash of the proposal UTxO to critique"),
+      // Note: a bare .default() without .optional() is reported as *required* by the
+      // SDK's isSchemaOptional() under zod/v4 (it returned optional under v3). That
+      // helper is only used for server.prompt() argument listing, which this codebase
+      // does not use — harmless for server.tool(), but relevant if prompts are added.
       proposalOutputIndex: z.number().default(0).describe("Output index of the proposal UTxO"),
       critiqueDocument: z.string().optional().describe("Full critique document as JSON string. Uploaded to IPFS via Filebase; hash and CID computed automatically."),
       critiqueHash: z.string().optional().describe("blake2b_256 hash of critique document (64 hex chars). Required if critiqueDocument is not provided."),

test/smoke/tool-inventory.test.ts

@@ -92,7 +92,7 @@ describe('tool inventory smoke test', () => {
     const added = actualNames.filter((name) => !EXPECTED_TOOLS.includes(name));
     const removed = EXPECTED_TOOLS.filter((name) => !actualNames.includes(name));
 
-    assert.deepEqual(
+    assert.deepStrictEqual(
       actualNames,
       EXPECTED_TOOLS,
       'Tool inventory drifted from the checked-in snapshot in test/smoke/tool-inventory.test.ts.\n' +
@@ -109,7 +109,7 @@ describe('tool schema snapshot', () => {
     const missingFromSnapshot = actualNames.filter((name) => !snapshotNames.includes(name));
     const staleInSnapshot = snapshotNames.filter((name) => !actualNames.includes(name));
 
-    assert.deepEqual(
+    assert.deepStrictEqual(
       snapshotNames,
       actualNames,
       'test/smoke/tool-schemas.snapshot.json keys do not match the live tool set.\n' +
@@ -119,7 +119,7 @@ describe('tool schema snapshot', () => {
     );
   });
 
-  // One assertion per tool (rather than a single deepEqual over the whole
+  // One assertion per tool (rather than a single deepStrictEqual over the whole
   // 23-tool map) so a failure names the specific tool and shows a readable
   // diff of just that tool's schema, instead of "objects differ" over an
   // unreadable combined structure.
@@ -130,7 +130,7 @@ describe('tool schema snapshot', () => {
         live,
         `Tool "${toolName}" is in the snapshot but was not returned by the live server's listTools().`
       );
-      assert.deepEqual(
+      assert.deepStrictEqual(
         live.inputSchema,
         schemaSnapshot[toolName],
         `inputSchema for "${toolName}" differs from the checked-in snapshot in test/smoke/tool-schemas.snapshot.json.\n` +