M12: preview text structure proposals for auto-tagging (#1383)

* M12: preview text structure proposals for auto-tagging

* Auto-tag preview: no unregistered command, allowed on copy-restricted files like a11y.check

The preview is read-only with no UI command yet, like render_preview, so it no
longer names the Planned a11y.autotag catalog id (tool_table_is_well_formed).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

* M12: preview text structure proposals for auto-tagging

* Keep read-only auto-tag preview separate from unavailable command

---------

Co-authored-by: Brandon Thomas <[email protected]>
Co-authored-by: Claude Opus 5.5 <[email protected]>

docs/gaps.md

@@ -182,14 +182,16 @@ update the numbers.
 - **Impact:** government and legal users sign with tokens and need B-LT/B-LTA.
 - **Estimate:** 40–70 h; tokens need hardware to test. **Doc:** [pdf-spec-parity.md](pdf-spec-parity.md).
 
-### 11. Accessibility: checker only, no tagging tools
+### 11. Accessibility: no automatic structure creation
 
-- **Missing:** autotag (document and fields), Tags, Order and Content panels, tag properties,
-  Reading Order tool, artifact marking, table editor, role map, Make Accessible action, Read Out
-  Loud; full keyboard operation of PdfCraft itself and a screen-reader audit.
-- **Evidence:** all 32 checker rules shipped, but 21 tagging and reading features planned;
+- **Missing:** apply auto-tag proposals to marked content and a valid parent tree, autotag fields,
+  visual Tags, Order and Content panels, Reading Order tool, table editor, Make Accessible action,
+  Read Out Loud; full keyboard operation of PdfCraft itself and a screen-reader audit.
+- **Evidence:** all 32 checker rules, figure alt text, tag property and sibling order edits, and
+  a bounded text-only auto-tag preview exist. The preview does not write PDF structure;
   `a11y.keyboard-only` (P0) planned, `a11y.app-screen-reader` partial.
-- **Impact:** remediation work is impossible; PdfCraft itself is not yet usable without a mouse.
+- **Impact:** untagged files still need another editor to build their structure; PdfCraft itself is
+  not yet usable without a mouse.
 - **Estimate:** 40–70 h. **Doc:** [target-app-parity.md](target-app-parity.md).
 
 ### 12. No measured fidelity harness against Acrobat

docs/roadmap.md

@@ -95,7 +95,7 @@ total matches the parity estimate.
 | M9 | Signatures (PAdES, validation) | 160–280 | 60% | 40–70 | Done: new `sign` crate (DER, X.509, CMS, PKCS #12 on RustCrypto; aws-lc-rs for RSA private keys); PAdES B-B signing (visible, invisible, existing fields, certification with DocMDP); validation with trust store and changes-after-signing classification; self-signed digital IDs; Signatures panel, message bar, sign dialogs; agent tools. Checked with pdfsig and OpenSSL.<br>Done since: macOS Keychain and Windows Current User Personal store signing (software-backed CNG keys), certificate viewer, signed documents protected from rewrites. Missing: timestamps (B-T), LTV (DSS, OCSP, CRL), FieldMDP, smart cards, PKCS #11 |
 | M10 | OCR, create, export, print | 200–350 | 33% | 120–215 | Done: create from blank/text/PNG/JPEG/TIFF (multi-page)/GIF/BMP; export PNG/JPEG/TIFF and text; Print (Acrobat's sizing, n-up, booklet, poster, comments & forms, preview, the CUPS and Windows spoolers, print-ready PDF).<br>Done since: embedded/72/custom DPI choices for image imports; export all images; OCR (searchable image for pages, ranges and multiple files); single-sided cut-and-stack imposition with cut marks, through Print and doc_print; architectural/ANSI/large ISO sheet presets, Match page at 100% and PDF-scale preview (#599 follow-up); Create PDF from multiple files (PDFs, images and text, edited as pages in the grid); OCR can also read pictures on pages that have text, without adding that text twice (#1028). Done since: Word invoice export uses borderless inferred tables, floating positioned text/artwork only where text overlaps an image or is rotated, and per-page sizes, covered by synthetic invoice automation regressions (#773); printing on the web through the browser's print dialog, sheets drawn by PdfCraft (gap 4). Missing: OCR languages beyond Latin, editable-text OCR output, full Office layout fidelity/import |
 | M11 | Optimize, preflight, PDF/A/X/UA, print production | 200–350 | 18% | 80–140 | Done: new `optimize` crate: Reduce File Size and the PDF Optimizer (images measured where drawn, bicubic downsampling, JPEG/ZIP recompression only when smaller, discard objects and user data, Flate clean-up, resource merging, object streams). Missing: fonts and transparency panels, space audit, preflight, PDF/A/X/UA |
-| M12 | Accessibility, compare, measure, search, XFA | 200–380 | 30% | 90–160 | Done: new `a11y` crate with the Accessibility Checker (all 32 rules, report, Fix/Skip/Explain, options dialog and results panel, agent tools). Locatable figure, annotation and form findings highlight their page bounds.<br>Done since: 2D distance, perimeter and area measurements with persistent viewport calibration, snapping, live information and CSV export. Missing: autotag, Tags/Order/Content panels, Reading Order tool, alt-text workflow, compare, geospatial/3D measurement, search index, XFA |
+| M12 | Accessibility, compare, measure, search, XFA | 200–380 | 30% | 90–160 | Done: new `a11y` crate with the Accessibility Checker (all 32 rules, report, Fix/Skip/Explain, options dialog and results panel, agent tools). Locatable figure, annotation and form findings highlight their page bounds.<br>Done since: 2D distance, perimeter and area measurements with persistent viewport calibration, snapping, live information and CSV export; a bounded, text-only auto-tag proposal tool for one page. Missing: writing proposed tags and parent tree, field autotag, visual Tags/Order/Content panels, Reading Order tool, compare, geospatial/3D measurement, search index, XFA |
 | M13 | Automation (MCP, Action Wizard, CLI) + AI providers | 60–120 | 45% | 25–45 | Done: MCP resources (document info, text, page images); headless tool table (123 tools incl. signing, optimizing, initial view, links, stamps, data exchange, comment review, forms authoring and scripts, redaction, sanitize, print, add content), opt-in MCP server over stdio, CLI `run`/`tools` (closed stdout pipes exit cleanly), UI control channel with drag. Missing: Action Wizard, AI providers<br>Done since: CLI run and MCP reject missing, empty, repeated and option-valued --root arguments before any tool/script execution or MCP initialization. A single-hyphen directory name remains valid; synthetic CLI regressions preserve a would-be overwritten file. `text_find` also caps the per-page match ranges it materializes at the remaining result limit plus one continuation match. |
 | M14 | 1.0 polish: performance, localization, installers | 120–250 | 15% | 80–150 | Done: PhotoCraft's translation system (`i18n/`: TSV catalogs, `tl!`, command-id and plural entries, system-language detection, strict catalog tests); every dialog, panel and notice goes through `tl!`. Catalogs of ≈ 2,000–2,140 entries for Japanese, Simplified and Traditional Chinese, Russian, Bulgarian, German, Spanish, French, Telugu, Hungarian, Ukrainian, Italian, Brazilian Portuguese and Arabic (logical-order catalog put into display order; layout not yet mirrored); Czech covers the menus. Signed and notarized macOS builds, signed Windows installers (x64, x86, ARM64), AppImage, deb, rpm, Flatpak and FreeBSD packages. #307 (bounded large-PDF memory): shared resource indexes and parser metadata, lazy inspection, bounded caches; a 9,156-page file inspects in ≈ 1.8 s at ≈ 500 MiB instead of exceeding 10 GiB. Edits let go of the previous working file before writing the next (a 1 GiB file peaks at two copies while editing, not three; gap 13). Shortcut display uses localized modifier/key names across menus, toolbar, palette, Help and tooltips (#496). Validated candidate (macOS raster probe; Windows runtime unverified): the Windows policy changes only embedded JetBrains Mono; horizontal alpha-edge energy per ink improves 2.78%, 3.87% and 1.59% at 100%, 125% and 150%, and is down 0.79% at 200%. Inter is pixel-identical; layout hashes, glyph coverage and the 8 MiB atlas are unchanged. Timing and RSS ranges overlap, with no improvement claimed. Estimates unchanged. Missing: a right-to-left layout, a Chinese UI face in releases, Hindi/Indonesian/Korean/Vietnamese, file-backed input and global memory budgets, performance budgets, keyboard-only operation |
 | M13 | Automation (MCP, Action Wizard, CLI) + AI providers | 60–120 | 45% | 25–45 | Done: MCP resources (document info, text, page images); headless tool table (123 tools incl. signing, optimizing, initial view, links, stamps, data exchange, comment review, forms authoring and scripts, redaction, sanitize, print, add content), opt-in MCP server over stdio, CLI `run`/`tools` (closed stdout pipes exit cleanly), UI control channel with drag. Missing: Action Wizard, AI providers |
@@ -143,6 +143,7 @@ M2 (renderer), M7 (content editing), M10 (OCR and Office), M11 (Preflight and st
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-12 | minor | M12: bounded text-only auto-tag preview through the engine and automation; actual PDF structure writing and visual review remain open. Estimates unchanged. |
 | 2026-10-12 | minor | M7: keep added Arabic copy/search in typing order with per-line ActualText; preserve that order in the editor and keep visual runs separate. Font-independent regressions and tool save/reopen coverage; font fallback and bidi typing remain partial. Estimates unchanged. |
 | 2026-10-12 | minor | M3: case-insensitive Find matches normal, final and capital Greek sigma; exact search, word boundaries, glyph ranges and match limits have regression coverage. The tab-menu test uses Finder on macOS. Estimates unchanged. |
 | 2026-10-12 | minor | M14: Windows low-DPI JetBrains Mono hinting candidate; raster and layout evidence recorded without a Windows runtime claim. Estimates unchanged. |