fix: prevent false link-check failures and harden health/workflow errors

Address three review findings from the Go rewrite:\n\n- checker: update PartitionLinks to only classify HTTP(S) URLs as external links.\n  This skips markdown-relative targets (for example  and anchors) so\n  non-URL entries are no longer sent to HTTP validation and do not produce\n  deterministic "unsupported protocol scheme" failures.\n\n- health command: stop ignoring LoadHealthCache errors.\n  Return a user-facing "load cache" error when the cache file is unreadable\n  or invalid instead of allowing a nil cache panic on Merge.\n\n- broken links workflow: remove masked execution behavior from the link check\n  step. Capture awesome-docker check exit code, set has_errors=true on any\n  non-zero exit, and expose the exit code in the generated issue body so\n  checker failures are visible and cannot incorrectly close the tracking issue.\n\nTest coverage updates:\n- extend checker partition test to include markdown-relative/anchor targets\n  and verify they are not treated as external URLs.\n- add cache test for invalid YAML load failure.

internal/cache/cache_test.go

@@ -78,6 +78,22 @@ func TestLoadHealthCacheMissing(t *testing.T) {
 	}
 }
 
+func TestLoadHealthCacheInvalidYAML(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "health.yaml")
+	if err := os.WriteFile(path, []byte("entries:\n  - url: [not yaml"), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	hc, err := LoadHealthCache(path)
+	if err == nil {
+		t.Fatal("expected error for invalid YAML")
+	}
+	if hc != nil {
+		t.Fatal("expected nil cache on invalid YAML")
+	}
+}
+
 func TestMerge(t *testing.T) {
 	hc := &HealthCache{
 		Entries: []HealthEntry{

internal/checker/github.go

@@ -3,6 +3,7 @@ package checker
 import (
 	"context"
 	"fmt"
+	"net/url"
 	"strings"
 	"time"
 
@@ -43,12 +44,20 @@ func ExtractGitHubRepo(url string) (owner, name string, ok bool) {
 	return parts[0], parts[1], true
 }
 
-// PartitionLinks separates URLs into GitHub repos and external links.
+func isHTTPURL(raw string) bool {
+	u, err := url.Parse(raw)
+	if err != nil {
+		return false
+	}
+	return u.Scheme == "http" || u.Scheme == "https"
+}
+
+// PartitionLinks separates URLs into GitHub repos and external HTTP(S) links.
 func PartitionLinks(urls []string) (github, external []string) {
 	for _, url := range urls {
 		if _, _, ok := ExtractGitHubRepo(url); ok {
 			github = append(github, url)
-		} else {
+		} else if isHTTPURL(url) {
 			external = append(external, url)
 		}
 	}

internal/checker/github_test.go

@@ -41,6 +41,8 @@ func TestPartitionLinks(t *testing.T) {
 		"https://example.com/tool",
 		"https://github.com/moby/moby",
 		"https://github.com/user/repo/issues",
+		"dozzle",
+		"#projects",
 	}
 	gh, ext := PartitionLinks(urls)
 	if len(gh) != 2 {