chore: add sethLabels deployment-fork scaffold

Adds Seth's homelab convention files on top of upstream glabels-qt master:
CLAUDE.md (project instructions), IDEA.md (brief), DECISIONS.md (decision
log, empty), and the kickoff handoff under .claude/handoffs/. Appends a
clearly-marked sethLabels section to .gitignore for .backup/, the
GITEA_API.md symlink, .env files, and handoff drafts.

This is the only non-upstream commit on main. All preceding history is
authored by the glabels.org team (Jaye Evins et al.) and untouched.
Future upstream merges should fast-forward or rebase cleanly since the
scaffold lives in distinct files at repo root.

No source-code changes. License unchanged (GPL-3.0).

.gitignore

@@ -40,3 +40,16 @@ TEST-DATA
 SAV*
 OLD*
 
+# === sethLabels (deployment fork) additions ===
+# Local backup snapshots (per ~/.claude/CLAUDE.md safety rule)
+.backup/
+
+# Local-only symlink to ~/bin/GITEA_API.md (target is outside the repo)
+GITEA_API.md
+
+# Secrets / env
+.env
+.env.*
+
+# Handoff drafts (operator scratch — final handoffs ARE committed)
+.claude/handoffs/*.draft.md