docs: update documentation to reflect v1.6.0 features as available (#185)

* docs: update documentation to reflect v1.6.0 features as available

This commit updates all documentation to reflect that v1.6.0 features
are now available (not planned):

Migration Guides:
- FROM_SQLFLUFF.md: Updated linting rules (10 rules L001-L010), auto-fix,
  VSCode extension, and .gosqlx.yml config as available in v1.6.0
- FROM_PG_QUERY.md: Updated JSON/JSONB operators as supported in v1.6.0

Documentation Updates:
- Updated version references from v1.5.x to v1.6.0 across all docs
- Added v1.6.0 upgrade section to UPGRADE_GUIDE.md
- Updated COMPARISON.md with v1.6.0 features and performance data
- Updated CLAUDE.md production status to v1.6.0+
- Updated performance_baselines.json to v1.6.0

Key v1.6.0 Features Now Documented:
- PostgreSQL Extensions (LATERAL JOIN, JSON/JSONB operators, DISTINCT ON)
- Language Server Protocol (LSP) server
- VSCode Extension
- 10 Linting Rules (L001-L010) with auto-fix
- .gosqlx.yml configuration file support
- go-task Taskfile.yml
- Structured error codes (E1001-E3004)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* docs: comprehensive v1.6.0 feature documentation update

Based on parallel agent review of all documentation, this commit updates:

Migration Guides:
- FROM_SQLFLUFF.md: Fixed "Coming in v1.5.0" → "Available in v1.6.0" for linting
- FROM_SQLFLUFF.md: Updated FAQ to reflect 10 linting rules now available
- FROM_PG_QUERY.md: Fixed "planned for v1.5.0" → "planned for future release"

SQL Compatibility (SQL_COMPATIBILITY.md):
- LATERAL JOIN: Updated from "10% Syntax" to "95% Full support"
- JSON/JSONB: Updated from "30% Syntax" to "95% Full support" with all operators
- Added DISTINCT ON: 95% Full support
- Added FILTER clause: 95% Full support
- Added RETURNING clause: 95% Full support

Comparison Guide (COMPARISON.md):
- Updated linting from "❌ Planned" to "✅ 10 rules (L001-L010)"
- Updated limitations section to reflect 10 rules available

Documentation Index (docs/README.md):
- Updated all document versions from v1.5.1 to v1.6.0
- Updated dates from 2025-11 to 2025-12

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* docs: add dedicated LSP, linting, and configuration guides with PostgreSQL examples

New Documentation:
- docs/LSP_GUIDE.md: Complete Language Server Protocol guide covering
  IDE integration, features, error codes, and troubleshooting
- docs/LINTING_RULES.md: Full reference for all 10 linting rules (L001-L010)
  with examples, severity levels, and auto-fix capabilities
- docs/CONFIGURATION.md: Comprehensive configuration guide for .gosqlx.yml
  with schema documentation, defaults, and best practices

New PostgreSQL Feature Examples:
- examples/postgresql/lateral-join/: LATERAL JOIN parsing demonstrations
- examples/postgresql/jsonb-operators/: JSON/JSONB operator support
  (->/->>/#>/#>>/@>/<@/?/?|/?&/#-)
- examples/postgresql/filter-clause/: FILTER clause for conditional aggregation
- examples/postgresql/returning-clause/: RETURNING clause for DML statements

Updated:
- examples/README.md: Added new examples to documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Ajit Pratap Singh <ajitpratapsingh@Ajits-Mac-mini.local>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: 3 people

CLAUDE.md

@@ -6,7 +6,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 GoSQLX is a **production-ready**, **race-free**, high-performance SQL parsing SDK for Go that provides lexing, parsing, and AST generation with zero-copy optimizations. The library is designed for enterprise use with comprehensive object pooling for memory efficiency.
 
-### **Production Status**: ✅ **VALIDATED FOR PRODUCTION DEPLOYMENT** (v1.5.1+)
+### **Production Status**: ✅ **VALIDATED FOR PRODUCTION DEPLOYMENT** (v1.6.0+)
 - **Thread Safety**: Confirmed race-free through comprehensive concurrent testing
 - **Performance**: 1.38M+ operations/second sustained, up to 1.5M peak with memory-efficient object pooling
 - **International**: Full Unicode support for global SQL processing
@@ -471,7 +471,7 @@ These mistakes have been made before - avoid them:
 - ✅ Allows for comprehensive testing and validation before tagging
 - ✅ Enables rollback if critical issues are found before release
 
-## Current SQL Feature Support (v1.5.1+)
+## Current SQL Feature Support (v1.6.0)
 
 ### GROUPING SETS, ROLLUP, CUBE (SQL-99 T431) - Complete ✅
 ```sql

README.md

@@ -145,7 +145,7 @@ gosqlx analyze "SELECT COUNT(*) FROM orders GROUP BY status"
 # Parse SQL to AST representation
 gosqlx parse -f json complex_query.sql
 
-# Unix Pipeline Support (NEW in v1.5.0)
+# Unix Pipeline Support
 cat query.sql | gosqlx format                    # Format from stdin
 echo "SELECT * FROM users" | gosqlx validate     # Validate from pipe
 gosqlx format query.sql | gosqlx validate        # Chain commands

docs/COMPARISON.md

@@ -1,7 +1,7 @@
 # GoSQLX vs Alternatives: Comprehensive Comparison
 
-**Last Updated:** 2025-11-28
-**GoSQLX Version:** v1.5.1
+**Last Updated:** 2025-12-11
+**GoSQLX Version:** v1.6.0
 
 This guide helps you choose the right SQL parsing tool for your needs. We provide an honest assessment of GoSQLX's strengths and limitations compared to popular alternatives.
 
@@ -19,7 +19,7 @@ This guide helps you choose the right SQL parsing tool for your needs. We provid
 | **Zero Dependencies** | ✅ Yes | ❌ No | ❌ No | ✅ Yes | ⚠️ Minimal |
 | **SQL Validation** | ✅ Fast | ✅ Rules-based | ❌ No | ✅ Yes | ✅ Yes |
 | **SQL Formatting** | ✅ Fast | ✅ Full | ✅ Opinionated | ⚠️ Basic | ❌ No |
-| **Linting Rules** | ❌ Planned | ✅ 60+ rules | ❌ No | ❌ No | ❌ No |
+| **Linting Rules** | ✅ 10 rules (L001-L010) | ✅ 60+ rules | ❌ No | ❌ No | ❌ No |
 | **Multi-Dialect** | ✅ 5 dialects | ✅ 60+ dialects | ⚠️ Limited | ⚠️ 4 dialects | ❌ PostgreSQL only |
 | **CLI Tool** | ✅ Fast | ✅ Feature-rich | ✅ Simple | ❌ No | ⚠️ Limited |
 | **Library API** | ✅ Simple | ✅ Complex | ⚠️ Limited | ✅ Full | ✅ Full |
@@ -190,8 +190,8 @@ SQLFluff:    ~50 KB   (25x)
 
 **Don't Choose GoSQLX if:**
 
-❌ **You need linting rules**
-- SQLFluff has 60+ rules, GoSQLX has 0 (planned)
+⚠️ **You need comprehensive linting (60+ rules)**
+- SQLFluff has 60+ rules, GoSQLX has 10 rules (L001-L010) in v1.6.0
 
 ❌ **You need 60+ SQL dialects**
 - GoSQLX supports 5 dialects
@@ -311,6 +311,6 @@ See individual migration guides for code examples and patterns.
 ---
 
 **Last Updated:** 2025-11-28
-**Version:** v1.5.1
+**Version:** v1.6.0
 
 *Benchmark numbers are reproducible. See `/benchmarks` directory.*