feat: add LSP server, VSCode + DataGrip extensions, release infra, autofix

- pkg/lsp: JSON-RPC 2.0 LSP server (formatting, diagnostics, codeAction quick-fixes)
- cmd/pgtidy: lsp and config subcommands
- pkg/diagnostics: TextFix struct for byte-range autofixes
- pkg/lint: MIG001/MIG003 autofixes, ApplyFixes helper, --fix flag on lint command
- editors/vscode: TypeScript extension with LanguageClient, showVersion/showConfig/formatDocument commands, logo
- editors/datagrip: Gradle JetBrains plugin via LSP4IJ, pluginIcon
- .goreleaser.yaml, .github/workflows: CI + release pipeline
- Makefile: snapshot, release, vscode-compile, vscode-package targets
- go.mod + all imports: module path updated to git.warky.dev/wdevs/pgtidy
- assets: logo files (256px, 128px, 1024px, ico)

pkg/diagnostics/diagnostics.go

@@ -12,6 +12,15 @@ const (
 	SeverityHint    Severity = "hint"
 )
 
+// TextFix is a byte-range replacement that can be applied to the source SQL.
+// Replace src[Offset:End] with New. An insertion has Offset == End.
+type TextFix struct {
+	Offset int    // byte offset in source (inclusive)
+	End    int    // byte offset in source (exclusive)
+	New    string // replacement text
+	Title  string // short description shown in editor UI
+}
+
 // Diagnostic is a single lint finding.
 type Diagnostic struct {
 	// RuleID is the stable identifier for the rule that produced this finding
@@ -27,4 +36,6 @@ type Diagnostic struct {
 	Line int
 	// Col is the 1-based column number of the finding.
 	Col int
+	// Fix is non-nil when an autofix is available for this diagnostic.
+	Fix *TextFix
 }