refactor: inject plugin version at build time via ldflags

Replace hardcoded Version string in Manifest() with a package-level
var that goreleaser populates via -ldflags -X. This ensures the
plugin's reported Manifest().Version matches the release tag, so the
workflow engine's requires.plugins[].version check passes.

Also add sed before-hook to bump plugin.json at release time.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: intel352

.goreleaser.yaml

@@ -5,6 +5,7 @@ project_name: workflow-plugin-github
 before:
   hooks:
     - go mod tidy
+    - "sed -i.bak 's/\"version\": \".*\"/\"version\": \"{{ .Version }}\"/' plugin.json && rm -f plugin.json.bak"
 
 builds:
   - id: workflow-plugin-github
@@ -20,6 +21,8 @@ builds:
     goarch:
       - amd64
       - arm64
+    ldflags:
+      - -s -w -X github.com/GoCodeAlone/workflow-plugin-github/internal.Version={{.Version}}
 
 archives:
   - id: workflow-plugin-github

internal/plugin.go

@@ -6,6 +6,10 @@ import (
 	sdk "github.com/GoCodeAlone/workflow/plugin/external/sdk"
 )
 
+// Version is set at build time via -ldflags
+// "-X github.com/GoCodeAlone/workflow-plugin-github/internal.Version=X.Y.Z"
+var Version = "dev"
+
 // webhookRouteConfig is the config fragment YAML that declares the GitHub
 // webhook HTTP route so the engine's HTTP server registers it via the normal
 // config pipeline instead of the unreachable global DefaultServeMux.
@@ -32,7 +36,7 @@ func NewGitHubPlugin() sdk.PluginProvider {
 func (p *githubPlugin) Manifest() sdk.PluginManifest {
 	return sdk.PluginManifest{
 		Name:        "workflow-plugin-github",
-		Version:     "1.0.1",
+		Version:     Version,
 		Author:      "GoCodeAlone",
 		Description: "GitHub integration plugin: webhook handling, GitHub Actions, PRs, issues, releases, and deployments",
 	}