feat(ui): add outline/fill icon-swap pattern for aside icon bar

Introduce data-icon-swap attribute with paired outline/fill <i> elements.
CSS toggles to filled icon on hover and active state. Module slots
auto-derive fill variant from icon name, with explicit icon_fill override
for icons without a fill counterpart (e.g. bi-headset). Add enforcement
script bin/icon-swap-check.sh.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bin/icon-swap-check.sh

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+# ─────────────────────────────────────────────────────────────
+# icon-swap-check.sh — Enforce outline/fill icon-swap pattern
+# in the aside icon bar.
+#
+# Every <button> and <a> inside aside.aside-icon-bar must use
+# data-icon-swap with two <i> children:
+#   <i class="bi bi-*" data-icon="outline"></i>
+#   <i class="bi bi-*" data-icon="fill"></i>
+#
+# Usage:  bin/icon-swap-check.sh
+# Exit:   0 = OK, 1 = violations found
+# ─────────────────────────────────────────────────────────────
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+ICON_BAR_TEMPLATE="$ROOT/templates/partials/app-main-aside-icon-bar.phtml"
+ERRORS=0
+
+echo "=== Icon-swap pattern check ==="
+
+# ── 1. Core icon-bar template must exist ──
+if [[ ! -f "$ICON_BAR_TEMPLATE" ]]; then
+  echo "FAIL: Icon bar template not found: $ICON_BAR_TEMPLATE"
+  exit 1
+fi
+
+# ── 2. Every <button> and <a> in icon bar must have data-icon-swap ──
+BUTTONS_WITH_SWAP=$(grep -c 'data-icon-swap' "$ICON_BAR_TEMPLATE" 2>/dev/null || true)
+
+if [[ "$BUTTONS_WITH_SWAP" -eq 0 ]]; then
+  echo "FAIL: No data-icon-swap attributes found in icon bar template"
+  ERRORS=$((ERRORS + 1))
+fi
+
+# ── 3. Every data-icon-swap element must have both outline and fill children ──
+SWAP_COUNT=$(grep -c 'data-icon-swap' "$ICON_BAR_TEMPLATE" 2>/dev/null || true)
+OUTLINE_COUNT=$(grep -c 'data-icon="outline"' "$ICON_BAR_TEMPLATE" 2>/dev/null || true)
+FILL_COUNT=$(grep -c 'data-icon="fill"' "$ICON_BAR_TEMPLATE" 2>/dev/null || true)
+
+if [[ "$SWAP_COUNT" -ne "$OUTLINE_COUNT" ]]; then
+  echo "FAIL: Mismatch — $SWAP_COUNT data-icon-swap elements but $OUTLINE_COUNT data-icon=\"outline\" icons"
+  ERRORS=$((ERRORS + 1))
+fi
+
+if [[ "$SWAP_COUNT" -ne "$FILL_COUNT" ]]; then
+  echo "FAIL: Mismatch — $SWAP_COUNT data-icon-swap elements but $FILL_COUNT data-icon=\"fill\" icons"
+  ERRORS=$((ERRORS + 1))
+fi
+
+# ── 4. Module manifests with aside.tab_panel must declare icon ──
+for manifest in "$ROOT"/modules/*/module.php; do
+  [[ -f "$manifest" ]] || continue
+  MODULE_DIR="$(dirname "$manifest")"
+  MODULE_ID="$(basename "$MODULE_DIR")"
+
+  # Skip modules that don't declare aside.tab_panel
+  if ! grep -q "aside\.tab_panel" "$manifest"; then
+    continue
+  fi
+
+  # Check icon is declared
+  if ! grep -qE "'icon'[[:space:]]*=>[[:space:]]*'bi-" "$manifest"; then
+    echo "FAIL: Module '$MODULE_ID' declares aside.tab_panel but has no icon"
+    ERRORS=$((ERRORS + 1))
+  fi
+done
+
+# ── 5. CSS must define the data-icon-swap rules ──
+CSS_FILE="$ROOT/web/css/layout/app-aside-icon-bar.css"
+if [[ -f "$CSS_FILE" ]]; then
+  if ! grep -q '\[data-icon-swap\]' "$CSS_FILE"; then
+    echo "FAIL: Missing [data-icon-swap] CSS rules in $CSS_FILE"
+    ERRORS=$((ERRORS + 1))
+  fi
+else
+  echo "FAIL: Icon bar CSS not found: $CSS_FILE"
+  ERRORS=$((ERRORS + 1))
+fi
+
+# ── Result ──
+if [[ "$ERRORS" -gt 0 ]]; then
+  echo ""
+  echo "FAILED: $ERRORS violation(s) found."
+  echo "All icon-bar buttons/links must use the data-icon-swap pattern."
+  exit 1
+fi
+
+echo "OK: All icon-bar elements use the outline/fill swap pattern."
+exit 0