Test-quality audit: fix 2 prod bugs, strengthen weak tests, add mutation/fuzz/CI tooling (#5345)

* test(audit): add gremlins/rapid/coverage tooling + AUDIT.md scaffold

* test(audit): hygiene sweep (race-clean except logger global; Finding #2) + smell inventory

* test(audit): cover untested error/edge branches (TLS proxy+pin, migration tag cleanup=Finding #1)

* test(audit): strengthen internal/sub link tests (dedup key, TLS/Reality mapping, clash well-formedness)

* test(audit): property (rapid) + fuzz tests for joinHostPort/userinfo/pin/ParseLink

* test(audit): tighten frontend subSortIndex rejection assertions + wire coverage

* ci(audit): add shuffle gate + non-blocking race job (Finding #2) + fuzz-smoke; document mutation policy

* chore(audit): gitignore frontend coverage output

* test(audit): exhaustive whole-repo pass — strengthen 5 weak/fake tests (netproxy, CSP, modal per-protocol loops, schema coercions)

* docs(contributing): add Testing section (conventions, race/shuffle, fuzz, mutation policy); drop AUDIT.md ledger

* fix(logger,migration): guard logBuffer with mutex; execute legacy tag cleanup (tx.Exec); make CI race gate blocking

* ci(mutation): add nightly scoped gremlins workflow (informational artifacts)

* test(audit): strengthen runtime tests — baseURL scheme/port bounds, isNonEmptySlice, trafficReset

* test(audit): strengthen clash tests — reality field mapping + tcp-header validation

* test(audit): runtime — egress-proxy + content-type tests; drop redundant bp=='' branch

* test(audit): strengthen link parser/helper tests (defaultPort, splitComma, base64, canonicalQuery, tls/reality/transport mapping)

* test(audit): strengthen sub/xray/common/netsafe/mtproto/config/middleware tests (kill surviving mutants)

* test(audit): raise timeout on protocol-iteration modal tests (heavy re-renders, slow on CI)

* fix(logger): GetLogs returns at most c entries (off-by-one fix; addresses PR review)

* perf(logger): snapshot logBuffer under lock so GetLogs doesn't block logging; clarify fuzz-seed docs (addresses PR review)

frontend/src/test/protocols.test.ts

@@ -27,3 +27,35 @@ describe('InboundSettingsSchema fixtures', () => {
     });
   }
 });
+
+// The fixture tests above pin coerced values only via regenerable snapshots. These
+// assert the load-bearing transforms directly, so a broken coercion fails independently
+// of the snapshot baseline.
+describe('InboundSettingsSchema coercions', () => {
+  it('vmess: defaults alterId to 0 and coerces a string tgId to a number', () => {
+    const parsed = InboundSettingsSchema.parse({
+      protocol: 'vmess',
+      settings: { clients: [{ id: 'u1', email: 'a@b.c', tgId: '12345' }] },
+    });
+    if (parsed.protocol !== 'vmess') throw new Error('discriminator narrowed to the wrong protocol');
+    const client = parsed.settings.clients[0];
+    expect(client.alterId).toBe(0); // .default(0) injected for omitted field
+    expect(client.tgId).toBe(12345); // string -> number transform
+  });
+
+  it('vmess: a non-numeric tgId coerces to 0', () => {
+    const parsed = InboundSettingsSchema.parse({
+      protocol: 'vmess',
+      settings: { clients: [{ id: 'u1', email: 'a@b.c', tgId: 'not-a-number' }] },
+    });
+    if (parsed.protocol !== 'vmess') throw new Error('wrong protocol');
+    expect(parsed.settings.clients[0].tgId).toBe(0); // Number(v) || 0
+  });
+
+  it('vless: defaults decryption and encryption to "none"', () => {
+    const parsed = InboundSettingsSchema.parse({ protocol: 'vless', settings: { clients: [] } });
+    if (parsed.protocol !== 'vless') throw new Error('wrong protocol');
+    expect(parsed.settings.decryption).toBe('none');
+    expect(parsed.settings.encryption).toBe('none');
+  });
+});