feat(roms): add igir report + SNES header-strip ops scripts

igir-report.ps1: read-only igir report over the EmuDeck tree on valhalla,
matching ROMs by checksum against libretro's No-Intro + Redump DAT sets
(sparse-cloned + cached). Scoped (-Platforms) or whole-library (-All);
CSV per run under /storage1/igir/reports. Uses node:lts (alpine breaks
igir on musl) and metadat/no-intro (not the curated dat/ folder).

igir-strip-snes-headers.sh: reversible backup-then-strip of 512-byte SNES
copier headers (size%1024==512) that igir can't auto-detect, renaming to
.sfc so headered ROMs match headerless No-Intro.

scripts/igir-report.ps1

@@ -0,0 +1,95 @@
+#!/usr/bin/env pwsh
+# scripts/igir-report.ps1
+#
+# Run the igir ROM collection manager in REPORT mode (read-only) against the
+# EmuDeck tree at /storage1/Emulation/roms on valhalla, matching ROMs by
+# checksum against the full No-Intro + Redump DAT sets. Produces a CSV per run
+# under /storage1/igir/reports listing FOUND / MISSING / UNUSED per system.
+#
+# Nothing is moved, renamed, or deleted — the ROM tree is mounted read-only.
+#
+#   ./scripts/igir-report.ps1 -Platforms gba,snes,n64,psx   # scoped run (fast)
+#   ./scripts/igir-report.ps1 -All                          # whole library (SLOW: hashes everything)
+#   ./scripts/igir-report.ps1 -Platforms snes -UpdateDats   # refresh the cached DATs first
+#
+# Gotchas baked in (all learned the hard way — see memory igir-roms):
+#   * Uses the Debian `node:lts` image, NOT node:lts-alpine (igir silently
+#     dies on musl).
+#   * DATs come from libretro-database `metadat/no-intro` + `metadat/redump`
+#     (full sets with checksums), NOT the tiny curated top-level `dat/` folder.
+#   * SNES `.smc` copier headers (size%1024==512) are NOT auto-detected by igir
+#     and won't match headerless No-Intro until physically stripped. The `snes`
+#     folder was stripped 2026-06-06; if you add more headered SNES ROMs, strip
+#     them first (see scripts/igir-strip-snes-headers.sh) or they'll show UNUSED.
+
+[CmdletBinding()]
+param(
+    [string[]]$Platforms,
+    [switch]$All,
+    [switch]$UpdateDats,
+    [string]$Hostname = 'valhalla'
+)
+
+$ErrorActionPreference = 'Stop'
+$PSNativeCommandUseErrorActionPreference = $true
+$server = "ginnoir@$Hostname"
+
+if (-not $All -and (-not $Platforms -or $Platforms.Count -eq 0)) {
+    Write-Error "Specify -Platforms <name,name,...> (e.g. -Platforms gba,snes) or -All for the whole library."
+    exit 1
+}
+
+# Build the igir -i input args. -All scans the entire roms tree (heavy);
+# otherwise one -i per named platform folder.
+if ($All) {
+    $inputArgs = '-i /input'
+} else {
+    $inputArgs = ($Platforms | ForEach-Object { "-i /input/$_" }) -join ' '
+}
+$doPull = if ($UpdateDats) { '1' } else { '0' }
+
+# Remote logic runs on valhalla. Single-quoted here-string so PowerShell leaves
+# $vars for bash; INPUT_ARGS / DOPULL are injected below.
+$remote = @'
+set -uo pipefail
+DATS=/storage1/igir/dats/libretro-database
+REPORTS=/storage1/igir/reports
+mkdir -p "$REPORTS" /storage1/igir/dats
+
+# Sparse, blobless clone of just the No-Intro + Redump DAT dirs (cached & reused).
+if [ ! -d "$DATS/.git" ]; then
+  echo ">> Fetching libretro-database DATs (one-time sparse clone)..."
+  docker run --rm -v /storage1/igir:/w -w /w node:lts sh -c '
+    git clone --filter=blob:none --sparse --depth 1 \
+      https://github.com/libretro/libretro-database dats/libretro-database &&
+    cd dats/libretro-database &&
+    git sparse-checkout set metadat/no-intro metadat/redump'
+elif [ "__DOPULL__" = "1" ]; then
+  echo ">> Updating cached DATs..."
+  docker run --rm -v /storage1/igir:/w -w /w/dats/libretro-database node:lts git pull -q
+fi
+
+NI=$(find "$DATS/metadat/no-intro" -name '*.dat' | wc -l)
+RD=$(find "$DATS/metadat/redump" -name '*.dat' | wc -l)
+echo ">> DATs available: $NI No-Intro, $RD Redump"
+
+STAMP=$(date +%Y-%m-%dT%H-%M-%S)
+OUT="igir-report-$STAMP.csv"
+echo ">> Running igir report -> $REPORTS/$OUT"
+docker run --rm \
+  -v /storage1/Emulation/roms:/input:ro \
+  -v "$DATS":/dats:ro \
+  -v "$REPORTS":/output \
+  node:lts npx -y igir@latest report \
+    -d /dats/metadat/no-intro -d /dats/metadat/redump \
+    __INPUT_ARGS__ \
+    --report-output "/output/$OUT" 2>&1 | grep -vE 'npm notice|npm warn' || true
+echo ">> Done. CSV: /storage1/igir/reports/$OUT"
+'@
+
+$remote = $remote.Replace('__INPUT_ARGS__', $inputArgs).Replace('__DOPULL__', $doPull)
+# Strip CR so the remote bash never sees stray \r (this file may be CRLF on disk).
+$remote = $remote.Replace("`r", '')
+
+Write-Host "igir report on $server :: $(if ($All) {'ALL platforms'} else {$Platforms -join ', '})"
+ssh $server $remote