feat(export): add separate AML/PNG label export flows and improvements

[akira69]

Summary

This PR delivers dedicated label export flows for spool and filament labels, including AML/PNG export options and export-specific UX.

Why This Matters

• Keeps export behavior explicit and separate from print-only behavior.
• Adds practical export controls (ZIP packaging, filename templates, DPI/options).
• Makes exported filenames predictable, configurable, and visible before export.

Code Quality Compliance ✅

Per https://github.com/Donkie/Spoolman/wiki/Contribute#style

• ESLint (frontend) ✓ Fixed: control character regex
• Prettier (frontend) ✓ Fixed: 7 files formatting
• Ruff (backend) ✓
• Pre-commit hooks validated ✓

Code Quality Improvements 🔧

Performance Optimizations Applied:

• Added useCallback memoization to filament selector callbacks (filamentSelectModal.tsx):
  • selectUnselectFiltered, handleSelectItem, handlePageChange, handlePageSizeChange
  • Prevents unnecessary re-renders of child components (pagination, checkboxes, buttons)
  • Stable function references persist across renders
• Added useCallback memoization to spool selector callbacks (spoolSelectModal.tsx):
  • selectUnselectFiltered, handleSelectItem
  • Improves React.memo effectiveness for table and checkbox components
  • Consistent optimization pattern across both selection modals

Alignment with PR 846:

• Filament selector in export flow uses the same single debounced ?search= API call introduced in feat(printing): filament label printing foundation #846, so full-dataset search works in both print and export flows.

React Immutability Fixes Applied:

• Replaced prop mutations with spread copies in qrCodeExportDialog.tsx (×5 sites)
• Pattern: curPreset.field = value; updateCurrentPreset(curPreset) → updateCurrentPreset({ ...curPreset, field: value })

Module-Scope Extraction (exportDialog):

• Moved 9 PNG binary helpers (pngSignature, readUint32BE, writeUint32BE, isPng, getChunkType, getCrc32Table, crc32, createPngChunk, setPngDpiMetadata) from inside the ExportDialog component body to module scope
• These pure functions have no dependency on component state; recreating them on every render was wasteful
• getCrc32Table lazy-init IIFE renamed to CRC32_TABLE immediate IIFE — table computed once unconditionally at module load

What Changed

Export flow and routing

• Adds dedicated export routes/pages for spool and filament label export flows.
• Hooks export actions into the selection flow without changing selection-table UX behavior.
• Keeps return URL handling intact for selection → export → back navigation.

Export capabilities

• AML export path supports ZIP packaging.
• PNG export supports DPI/layout export options.
• Configurable filename templates for exported outputs.
• Duplicate filenames in one export are auto-suffixed (01, 02, 03, ...)
• Filename template control is now placed with export-format controls.
• Preview pane now shows per-item output filenames.

UI wording consistency

• Entity-specific titles:
  • Export Filament Labels
  • Export Spool Labels

Screenshots

The selection window with separate export labels button

• Specific wording for spools

• Specific wording for Filaments (implemented by feat(printing): filament label printing foundation #846 )

The new export Label page with AML export added and DPI selection for PNG

"Export as .zip" for both PNG and AML exports (one file per label inside the archive).

ZIP name to be exported shown :

• PNG spool labels.zip / AML spool labels.zip
• PNG filament labels.zip / AML filament labels.zip

Configurable individual label filename template

• Specific for spool and filament exports under the format/options area
• Default Spool: {filament.vendor.name}-{filament.material}-{filament.name}-{id}
• Default Filament: {vendor.name}-{material}-{name}
• Tooltip references template usage + duplicate suffix behavior.

Latest Fixes

• Export and print dialogs now handle older base_url settings without crashing when the value was stored as a plain string.
• Export state loading now tolerates the legacy string value "undefined" in saved local storage instead of crashing the export page.
• If a saved preset was deleted, the dialog now falls back to the first valid preset instead of getting stuck in a broken temporary state.
• Template value replacement now uses the same safer handling already applied in feat(printing): filament label printing foundation #846.
• The filament label/export selector now uses a single debounced ?search= API call (from feat(printing): filament label printing foundation #846), so full-dataset vendor and material searches work in the export flow too.

Manual Verification Completed

• ✓ Verified locally on March 27, 2026 via Playwright at http://127.0.0.1:9860.
• ✓ Opened spool and filament export flows and confirmed the explicit page titles render correctly.
• ✓ Set a legacy plain-string base_url value and confirmed both export and settings pages still load without crashing.
• ✓ Set legacy saved-state data to the string "undefined" and confirmed the export page recovers instead of failing during initialization.
• ✓ Deleted or invalidated the remembered preset, reopened the dialog, and confirmed it falls back to the first real saved preset.
• ✓ Searched the filament selector for vendor/material values that were not on page 1 and confirmed the single debounced ?search= flow returned full-dataset matches.
• ✓ Ran spool and filament AML exports, PNG exports, and ZIP exports and confirmed previews and filenames matched the generated files.
• ✓ Verified duplicate export filenames are auto-suffixed (01, 02, ...) and custom filename templates persist and reload correctly.

Testing Performed

• Frontend production build: ✓
• Targeted frontend lint on touched files: ✓
• Local branch image rebuilt and deployed for validation: ✓
• Playwright browser validation against http://127.0.0.1:9860: ✓
• Exported PNG at default and custom DPI and confirmed output dimensions changed as expected: ✓
• Exported AML files and ZIP packages for both spool and filament flows: ✓
• Verified filename templating, duplicate suffixing, selector pagination, preset persistence, and legacy setting recovery paths: ✓

Test Checklist

• Export Spool Labels page title displays correctly
• Export Filament Labels page title displays correctly
• PNG export generates valid images at default and custom DPI
• AML export generates valid AML files usable in Labelife
• ZIP packaging works for both PNG and AML exports
• Filename template applies correctly to exports (matches preview)
• Duplicate filenames get auto-suffixed (01, 02, 03...) in exports
• Dialog handles older base_url format without errors or crashes
• Filament selector pagination responds smoothly with callback memoization
• Spool selector checkbox interactions remain responsive
• Both modals render without console warnings related to callback changes

Merge Notes (Combined-Branch Integration) 🔀

Commit fba5e5d pre-patches four conflict hotspots discovered during combined-branch integration:

• useSetPrintSettings — returns the raw useSetSetting<>() mutation object directly; fixes .mutate() call patterns expected by callers in combined branches
• Dialog interfaces (QRCodePrintingDialog, QRCodeExportDialog) — extraTitleSettings?, extraInfoSettings?, extraExportSettings? props added with render sites; allows filament-specific settings rows to be injected from callers in other PRs without conflict
• FilamentSelectModal — onPrint made optional, onExport? + initialSelectedIds? added, conditional Export Labels button added; aligns with SpoolSelectModal pattern already in this PR
• otherModels.tsx — useSimpleSortedArrayQuery factory added, 4 verbose hooks refactored to 1-liners; identical to feat(ui/filters): searchable filter dropdown + bulk selection + query responsiveness #862's approach, so the two PRs auto-merge on this file instead of conflicting

Merge order: after #846, before #862.

Database Impact

• None.
• No migration, schema, or index changes.

Scope Mapping

• Feature requests addressed: AML/PNG export flows, ZIP packaging, configurable filename templates
• Deliberately excluded: Selection-page UX split (tracked in feat(printing/ui): Spool Print selection page UX Improvement #869), broader persisted UI state hardening (from fix(print): prevent white page when persisted state JSON is invalid #871)

PR Chain / Dependencies

1. Base dependency: #846 (required).
2. This PR is the export layer in the chain.
3. #857 (logo core) is stacked on top of this PR.
4. #872 (logo GitHub sync) is stacked on top of #857.

• The intended stacking order to get the full feature set of label improvements and logos is :

1. feat(printing): filament label printing foundation #846
2. feat(manufacturers): **Logos for vendors** logo-aware UI and label workflows (core, no bundled assets) #857
3. feat(export): add separate AML/PNG label export flows and improvements #860
4. feat(vendors/logos): add GitHub logo-pack sync workflow (no bundled assets) #872