chore: upgrade eval judge to Sonnet 4.6, update changelog

Switch LLM-as-judge evals from Haiku to Sonnet 4.6 for more stable,
nuanced scoring. Add changelog entry for all eval improvements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,21 @@
 # Changelog
 
+## Unreleased — 2026-03-14
+
+### Changed
+- Enriched 14 command descriptions with specific arg formats, valid values, error behavior, and return types
+- Fixed `header` usage from `<name> <value>` to `<name>:<value>` (matching actual implementation)
+- Added `cookie` usage syntax: `cookie <name>=<value>`
+- Enriched 4 snapshot flag descriptions with defaults, output paths, and behavior details
+- Snapshot flags section now shows long flag names (`-i / --interactive`) alongside short
+- Added ref numbering explanation and output format example to snapshot docs
+- Replaced hand-maintained server.ts help text with auto-generated `generateHelpText()` from COMMAND_DESCRIPTIONS
+- Upgraded LLM eval judge from Haiku to Sonnet 4.6 for more stable scoring
+
+### Added
+- Usage string consistency test: cross-checks `Usage:` patterns in implementation against COMMAND_DESCRIPTIONS
+- Pipe guard test: ensures no command description contains `|` (would break markdown tables)
+
 ## 0.3.3 — 2026-03-13
 
 ### Added

test/skill-llm-eval.test.ts

@@ -7,7 +7,7 @@
  * Requires: ANTHROPIC_API_KEY env var
  * Run: ANTHROPIC_API_KEY=sk-... bun test test/skill-llm-eval.test.ts
  *
- * Cost: ~$0.01-0.03 per run (haiku)
+ * Cost: ~$0.05-0.15 per run (sonnet)
  */
 
 import { describe, test, expect } from 'bun:test';
@@ -30,7 +30,7 @@ async function judge(section: string, prompt: string): Promise<JudgeScore> {
   const client = new Anthropic();
 
   const response = await client.messages.create({
-    model: 'claude-haiku-4-5-20251001',
+    model: 'claude-sonnet-4-6',
     max_tokens: 1024,
     messages: [{
       role: 'user',
@@ -158,7 +158,7 @@ describeEval('LLM-as-judge quality evals', () => {
 
     const client = new Anthropic();
     const response = await client.messages.create({
-      model: 'claude-haiku-4-5-20251001',
+      model: 'claude-sonnet-4-6',
       max_tokens: 1024,
       messages: [{
         role: 'user',