Update documentation with test findings and new testing commands

Add new sections to replit.md detailing known test issues, slow tests, and available test helpers, along with commands for isolation and timing-aware testing.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 0af6cbd9-213b-4067-92c7-061364010187
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Event-Id: e31b94b0-d6a9-46b6-b500-c1d9ff5f43ae
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replit.md

@@ -121,6 +121,52 @@ Reports are generated in `flaky-test-results/` including:
 - JSON data file with detailed per-test run history
 - Individual iteration JSON results for debugging
 
+### Isolation Testing for Specific Test Files
+To run a single test file multiple times and detect flakiness:
+```bash
+TEST=api.entries npm run test:flaky:isolate      # Test entries API
+TEST=api3.socket npm run test:flaky:isolate      # Test socket API
+FLAKY_ITERATIONS=20 TEST=security npm run test:flaky:isolate  # 20 iterations
+```
+
+### Timing-Aware Testing
+Run tests with timing warnings enabled to identify slow operations:
+```bash
+npm run test:timing          # Full suite with timing warnings
+npm run test:timing:single   # Single test file (set TEST env var)
+npm run test:slow            # Tests with slow threshold logging
+```
+
+### Known Test Issues (Last Analysis: January 2026)
+
+**Summary:** 177 passing, 10 failing, 8 pending
+
+#### Consistently Failing Tests (10 total)
+
+| Category | Test Name | Root Cause Analysis |
+|----------|-----------|---------------------|
+| **API3 Renderers (5 tests)** | SEARCH/HISTORY xml/csv content type tests + mock cleanup | XML/CSV renderer implementation may be incomplete or broken |
+| **API3 Deduplication** | should deduplicate document by created_at+eventType | Deduplication logic timing or race condition |
+| **API v1 Partial Failures** | devicestatus with large prediction arrays | Large document handling or timeout issue |
+| **Treatment API** | post single treatments in zoned time format | Timezone parsing or format issue |
+| **Bolus Wizard Preview (2 tests)** | IOB calculation + BWP pill display | Plugin logic or test data issue |
+
+#### Slow Tests Detected
+Multiple tests in `v1 API Batch Operations` exceed the 2000ms threshold:
+- Batch insert semantics tests (Loop carbs, Loop dose, glucose batches)
+- Large batch operations (100-item batches)
+- Trio pipeline scenarios
+- Response format validation
+
+These slow tests are potential sources of timeout-related flakiness in CI environments.
+
+#### Test Helpers Available
+The `tests/lib/test-helpers.js` module provides utilities to reduce flakiness:
+- `waitForConditionWithWarning()` - Polling-based waits instead of setTimeout
+- `waitForConditionAsync()` - Promise-based version for async/await
+- `startTestTimer()` - Monitor test execution time
+- `enableSetTimeoutWarnings()` - Detect setTimeout anti-patterns
+
 See `docs/test-specs/coverage-gaps.md` for aggregated coverage gaps across all areas.
 
 ## External Dependencies