init: centralized agent skills for Claude Code + Codex

- skills/ shared by both tools (open Agent Skills standard)
- portable cross-skill refs (root-relative, no ~/.claude hardcode)
- bin/link.sh bootstrap for non-Nix machines
- nix/home.nix + flake.nix for home-manager

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014SK5Lo7LQfwLRVdCv1A8uF

skills/impeccable/scripts/live/completion.mjs

@@ -0,0 +1,19 @@
+export function completionTypeForAcceptResult(eventType, acceptResult) {
+  if (eventType === 'discard') return acceptResult?.handled === true ? 'discarded' : 'error';
+  if (acceptResult?.handled === true && acceptResult?.carbonize === true) return 'agent_done';
+  if (acceptResult?.handled === true) return 'complete';
+  if (acceptResult?.mode === 'error') return 'error';
+  if (eventType === 'accept' && acceptResult?.previewMode === 'svelte-component') return 'error';
+  return 'agent_done';
+}
+
+export function completionAckForAcceptResult(eventId, completionType, acceptResult) {
+  const ack = { ok: true, type: completionType };
+  if (acceptResult?.handled === true && acceptResult?.carbonize === true) {
+    ack.final = false;
+    ack.requiresComplete = true;
+    ack.nextCommand = `live-complete.mjs --id ${eventId}`;
+    ack.message = 'Carbonize cleanup must be verified, then the session must be completed explicitly before polling again.';
+  }
+  return ack;
+}