fix(audit): close all missing-references rows in script audit

The audit's "missing references" table held 15 rows — 2 real doc bugs and
13 grep false-positives — making Pillar 3 Phase B triage noisier than it
needed to be.

- Wrote themes/engine/scripts/nomarchy-theme-next so SKILL.md's documented
  "cycle to next theme" command actually resolves.
- Scrubbed three stale `nomarchy-dev-*` references from SKILL.md (skill
  frontmatter, body, and Out-of-Scope list) — they hallucinated a workflow
  that doesn't exist and broke AI-assisted use of the skill.
- Added a line-context filter to both nomarchy-docs-scripts generators
  that drops `nomarchy-*` tokens appearing in Nix pname/derivation idents,
  /tmp/ and /etc/sudoers.d/ paths, nixosConfigurations.* / packages.*
  flake outputs, mktemp -t prefixes, systemd unit vars, ./result/bin/run-
  binaries, and docker container references.
- Added a small token-level denylist for five residual non-script
  identifiers (nomarchy-plymouth, nomarchy-sddm-theme, nomarchy-live,
  nomarchy-rev, nomarchy-windows) that survive line filtering because
  they appear as bare Nix list refs, comment backticks, or compose-heredoc
  identifiers.

Regenerated docs/SCRIPTS.md; the "Missing references" section is now
empty. Logged in docs/ROADMAP.md Shipped.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

themes/engine/scripts/nomarchy-theme-next

@@ -0,0 +1,24 @@
+#!/bin/bash
+set -e
+
+# Cycles to the next available theme (wraps from last back to first).
+
+mapfile -t THEMES < <(nomarchy-theme-list)
+TOTAL=${#THEMES[@]}
+
+if (( TOTAL == 0 )); then
+  notify-send "No themes available"
+  exit 1
+fi
+
+CURRENT=$(nomarchy-theme-current)
+INDEX=-1
+for i in "${!THEMES[@]}"; do
+  if [[ "${THEMES[$i]}" == "$CURRENT" ]]; then
+    INDEX=$i
+    break
+  fi
+done
+
+NEXT_INDEX=$(((INDEX + 1) % TOTAL))
+nomarchy-theme-set "${THEMES[$NEXT_INDEX]}"