feat: enhanced JSON Schema, LSP server, and canonical snippets for IDE support

[intel352]

Summary

Three major additions for IDE integration:

Enhanced JSON Schema Generator

• Per-module-type config validation using if/then conditionals keyed on type field
• Pipeline step schemas with step type enum and per-step config keys
• Trigger type schemas, imports, requires, platform sections
• GenerateApplicationSchema() for multi-workflow app configs
• Schema is ~271KB / 7500+ lines with comprehensive type validation

LSP Server (lsp/ + cmd/workflow-lsp-server/)

• Completions: module/step/trigger types, context-aware config keys, dependsOn module names, template functions inside {{ }}
• Diagnostics: unknown types, missing dependencies, unknown config keys, unclosed templates (with line/column positions via yaml.Node)
• Hover: module descriptions + config field tables, step/trigger type docs, template function signatures
• Document tracking: thread-safe store with YAML node tree and cursor position context detection
• Binary added to GoReleaser for cross-platform release builds

Canonical Snippets (schema/snippets*.go + wfctl snippets)

• 32 snippet definitions covering modules, steps, triggers, workflows, and structural blocks
• ExportSnippetsVSCode() — VSCode .code-snippets JSON format
• ExportSnippetsJetBrains() — JetBrains live template XML format
• wfctl snippets --format vscode|jetbrains|json subcommand

Test plan

• Schema tests: valid JSON, if/then for http.server, pipelines/requires/imports sections, application schema
• LSP tests: completions, diagnostics, hover, registry, document store, context detection
• Snippet tests: count, field validation, VSCode JSON validity, JetBrains XML validity
• golangci-lint clean

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds IDE support capabilities to the workflow project by introducing (1) a richer JSON Schema generator for config validation, (2) a new Language Server Protocol (LSP) server for YAML authoring assistance, and (3) canonical snippet exports (VSCode + JetBrains) surfaced via wfctl.

Changes:

• Enhanced JSON Schema generation with conditional per-module validation and additional top-level sections (pipelines/imports/requires/platform) plus an application-level schema.
• Added a new workflow-lsp-server binary and lsp/ package implementing completions, diagnostics, and hover for workflow YAML.
• Added canonical snippet definitions and exporters (VSCode JSON + JetBrains XML) plus a wfctl snippets subcommand.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
schema/schema.go	Expands schema model + generates enhanced workflow/application schemas with new sections and conditional validation.
schema/schema_enhanced_test.go	Adds tests validating generated schema shape and selected conditionals.
schema/snippets.go	Introduces canonical snippet definitions for common modules/steps/triggers/workflows/structure.
schema/snippets_export.go	Adds snippet export functions for VSCode JSON and JetBrains live templates XML.
schema/snippets_test.go	Adds tests for snippet completeness and export validity.
lsp/server.go	Implements LSP server wiring and stdio transport with diagnostics publishing.
lsp/registry.go	Builds an LSP registry from schema-known module/step/trigger/workflow types.
lsp/document.go	Adds a thread-safe document store and basic cursor-context detection.
lsp/diagnostics.go	Adds YAML-based diagnostics for unknown types, unknown config keys, dependsOn validation, and template closure.
lsp/completion.go	Adds context-aware completions for keys, types, dependsOn names, and template functions.
lsp/hover.go	Adds hover content for module types, module config keys, trigger types, and template functions.
lsp/lsp_test.go	Adds unit tests for registry population, document store behavior, diagnostics, completions, hover, and context detection.
cmd/workflow-lsp-server/main.go	Adds the LSP server entrypoint binary with build-time version injection.
cmd/wfctl/snippets.go	Adds wfctl snippets command to export snippets in multiple formats.
cmd/wfctl/main.go	Registers the new snippets subcommand in wfctl.
.github/workflows/release.yml	Adds cross-platform release builds for workflow-lsp-server.
go.mod / go.sum	Adds github.com/tliron/glsp and related indirect dependencies.