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/types.go

@@ -5,8 +5,9 @@ type Marker int
 
 const (
 	MarkerAbandoned Marker = iota // :skull:
-	MarkerPaid                    // :heavy_dollar_sign:
+	MarkerPaid                    // :yen:
 	MarkerWIP                     // :construction:
+	MarkerStale                   // :ice_cube:
 )
 
 // Entry is a single link entry in the README.