docs: REUSE.md introduced — catalog conventions map (canonical app, healthcheck families, traps) + minimal CLAUDE.md

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

CHANGELOG.md

@@ -1,5 +1,14 @@
 # Changelog
 
+## 2026-07-03 — docs: REUSE.md introduced
+
+Cross-repo reuse-map rollout (docs-only). New `REUSE.md`: catalog conventions verified against all
+53 apps — the canonical example app (paperless-ngx), `.felhom.yml` required fields, healthcheck
+family per image type (BusyBox wget / curl / Node / Python / DB sidecars), memory-limit convention,
+new-app checklist, and traps (gokapi entrypoint hack, legacy templates.json). Known README drift
+recorded in §6 (NOT fixed). Also a minimal `CLAUDE.md` carrying the REUSE.md pointer + maintenance
+rule (full CLAUDE.md is a separate task).
+
 ## 2026-06-29 — App-email: calcom + nextcloud (tls_mode=plaintext :2526 + nextcloud split-From)
 - **nextcloud** — `smtp_mapping` with `tls_mode: plaintext` (controller injects port 2526, the plaintext-only
   listener) + **split From** (`from_var=MAIL_FROM_ADDRESS` + `from_domain_var=MAIL_DOMAIN` → nextcloud@felhom.eu).