feat(import): v5.6.0 unified data import (phases 0-5)

- unified importer framework (app/services/importers/): normalized model,
  registry, common pipeline (hierarchy, attachments, collections, dedup),
  async jobs, dry-run preview, column->type mapping
- Phase 1: Obsidian, Notion, Logseq/Roam, HTML (Apple Notes/Bear/Ulysses/
  OneNote), Google Keep, generic Markdown
- Phase 2: typed CSV/TSV, Excel (openpyxl), generic JSON
- Phase 3: Word .docx (python-docx), PDF (pypdf), HTML folders
- Phase 4: Raindrop, Pocket, Readwise, Shaarli, Netscape bookmarks, .ics,
  OPML, Standard Notes, Gitea/GitHub issues (+labels/milestones)
- Phase 5: incremental re-sync (skip/update/duplicate), partial-error resume,
  forge repo files, URL web clipper (SSRF guard), batch multi-file + UI queue,
  Notion relation resolution, exportable JSON reports
- /import wizard, API /api/import/*, migration 9 (import_items, import_jobs)
- fix: property values stored by property id (correct DB view rendering)
- deps: openpyxl, beautifulsoup4, PyYAML, python-docx, pypdf
- 43 import tests; full suite 491 green; ruff clean
- bump version 5.11.5

app/services/importers/__init__.py

@@ -0,0 +1,58 @@
+"""FlowDeck — importers package (v5.6.0).
+
+Importing this package registers every built-in importer. Use
+:func:`parse_upload` to detect a source and :func:`run_import` to persist it.
+"""
+from __future__ import annotations
+
+from app.services.importers import (  # noqa: F401 - registration side effects
+    bookmarks,
+    calendar,
+    docx,
+    html_notes,
+    markdown,
+    notion,
+    obsidian,
+    opml,
+    outline,
+    pdf,
+    standard_notes,
+    tabular,
+)
+from app.services.importers.base import (  # noqa: F401
+    ImportAttachment,
+    Importer,
+    ImportPage,
+    ImportResult,
+    all_importers,
+    detect_importer,
+    get_importer,
+    list_sources,
+)
+from app.services.importers.jobs import (  # noqa: F401
+    create_job,
+    get_job,
+    list_jobs,
+    parse_upload,
+    start_import_job,
+)
+from app.services.importers.pipeline import preview_result, resolve_relations, run_import  # noqa: F401
+
+__all__ = [
+    "ImportAttachment",
+    "ImportPage",
+    "ImportResult",
+    "Importer",
+    "all_importers",
+    "detect_importer",
+    "get_importer",
+    "list_sources",
+    "create_job",
+    "get_job",
+    "list_jobs",
+    "parse_upload",
+    "start_import_job",
+    "preview_result",
+    "run_import",
+    "resolve_relations",
+]