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/migrations.py

@@ -375,3 +375,47 @@ def _migration_db_templates_validation(conn: sqlite3.Connection) -> None:
             (tpl["name"], tpl.get("icon", "📋"), tpl.get("description", ""),
              __import__("json").dumps(tpl.get("schema", []))),
         )
+
+
+@register(9, "v5.6.0: import items (dedup) + import jobs")
+def _migration_import_framework(conn: sqlite3.Connection) -> None:
+    """Unified import framework (Phase 0).
+
+    ``import_items``  — one row per imported page, keyed by workspace + source +
+                        external id, so re-importing the same vault is idempotent.
+    ``import_jobs``   — background import job status/history for UI polling.
+    """
+    conn.execute(
+        """
+        CREATE TABLE IF NOT EXISTS import_items (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            workspace_id INTEGER,
+            source TEXT NOT NULL DEFAULT '',
+            external_id TEXT NOT NULL DEFAULT '',
+            page_id INTEGER,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            UNIQUE(workspace_id, source, external_id)
+        )
+        """
+    )
+    conn.execute(
+        "CREATE INDEX IF NOT EXISTS idx_import_items_lookup "
+        "ON import_items(workspace_id, source, external_id)"
+    )
+    conn.execute(
+        """
+        CREATE TABLE IF NOT EXISTS import_jobs (
+            id TEXT PRIMARY KEY,
+            source TEXT NOT NULL DEFAULT '',
+            filename TEXT NOT NULL DEFAULT '',
+            status TEXT NOT NULL DEFAULT 'queued',
+            error TEXT NOT NULL DEFAULT '',
+            report_json TEXT NOT NULL DEFAULT '{}',
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        )
+        """
+    )
+    conn.execute(
+        "CREATE INDEX IF NOT EXISTS idx_import_jobs_created ON import_jobs(created_at)"
+    )