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>

.github/CONTRIBUTING.md

@@ -19,7 +19,8 @@ Please read and follow the [Code of Conduct](./CODE_OF_CONDUCT.md).
 - Prefer GitHub project/repository URLs over marketing pages.
 - Keep entries alphabetically sorted within their section.
 - Keep descriptions concise and concrete.
-- Use `:heavy_dollar_sign:` for paid/commercial services.
+- Use `:yen:` for paid/commercial services.
+- Use `:ice_cube:` for stale projects (2+ years inactive).
 - Do not use `:skull:`; archived/deprecated projects should be removed.
 - Avoid duplicate links and redirect variants.
 

.github/ISSUE_TEMPLATE/add-a-project.md

@@ -12,7 +12,7 @@ Repository link:
 Description (one sentence):
 Author:
 Why this should be in the list:
-Notes (`:heavy_dollar_sign:` if relevant):
+Notes (`:yen:` if relevant):
 
 Or directly write it:
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -25,4 +25,4 @@ Describe what changed and why.
 - [ ] Links point to project repositories (no duplicates or redirects)
 - [ ] Descriptions are concise and specific
 - [ ] Archived/deprecated projects were removed instead of tagged
-- [ ] Used `:heavy_dollar_sign:` only when applicable
+- [ ] Used `:yen:` only when applicable