Mark stale projects with 🧊, remove archived entries, add Arcane (#1267)

- Add 🧊 marker for 113 stale projects (2+ years inactive)
- Remove 4 archived repos (Centurion, notary, Minio, docker-ls)
- Remove 1 broken link (docker-lock / safe-waters)
- Add Arcane to the Web section
- Replace 💲 with 💴 across README and tooling
- Add 🧊 (MarkerStale) support to Go parser/linter
- Update CONTRIBUTING.md, PR template, issue template, and AGENTS.md

Closes #1260, relates to #1188, #1255

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

internal/parser/parser_test.go

@@ -44,7 +44,7 @@ func TestParseEntryWithMarkers(t *testing.T) {
 }
 
 func TestParseEntryMultipleMarkers(t *testing.T) {
-	line := `- [SomeProject](https://example.com) - A project. :heavy_dollar_sign: :construction:`
+	line := `- [SomeProject](https://example.com) - A project. :yen: :construction:`
 	entry, err := ParseEntry(line, 1)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
@@ -90,7 +90,7 @@ func TestParseDocument(t *testing.T) {
 
 ## Services
 
-- [ServiceC](https://example.com/c) - Does C. :heavy_dollar_sign:
+- [ServiceC](https://example.com/c) - Does C. :yen:
 `
 	doc, err := Parse(strings.NewReader(input))
 	if err != nil {