V4.6 Phase 5: UI boundaries and duplication

Fixes the three ui.instructions.md violations recorded as [HIGH-07] and extracts
the page-level duplication catalogued in review section 4.

Boundary violations
- jobs_page no longer imports session_scope or manages a transaction.
  store.create_document_job and store.create_job_for_document accept an optional
  session_factory and open their own session scope when the caller supplies
  neither a session nor a factory.
- sources_page no longer calls sqlalchemy.inspect. SourceService
  .read_latest_execution_attempt now returns a LatestExecutionAttempt read model
  carrying a plain transport_body_deferred flag, so ORM loader state stays inside
  the service. Rendered output is unchanged.
- Deletes ui/components/document_panzoom.py, its export, and its CSS. The
  component was exported but used by no page. Pan-zoom is planned for a clean
  reintroduction in V4.7 alongside the other photo/image work.

Extracted duplication
- ui/components/media_urls.py: pure upload-URL resolution taking upload_dir and
  base_url, replacing two identical ~60-line copies in sources_page and
  people_page.
- ui/components/guards.py: parse-then-render-terminal-message, replacing 28
  hand-written guard labels across five pages.
- ui/components/confirm_delete.py: the blocked-dependency notice and the
  delete/cancel action row, from four delete pages.
- ui/components/upload_panel.py: the auto-uploading file picker, from three
  pages. Source accept lists now derive from services.source_media
  .SOURCE_EXTENSIONS instead of being hard-coded.
- ui/components/table/registry.py: the two hand-rolled label-registry tables on
  the settings page now go through build_table, which gained selection and
  rows_per_page options.
- ui/components/formatters.py gains parse_uuid and parse_iso_date, replacing
  five and two private copies.
- ui/runtime.py owns resolve_runtime_settings, replacing three copies and
  removing get_settings from every page module.

[LOW-05]
- Upload handlers are annotated with events.UploadEventArguments.
- The Document and Person form builders return DocumentFormFields and
  PersonFormFields dataclasses instead of dict[str, Any].

Verification
- tests/test_ui_boundaries.py asserts no page imports a session scope, a session
  factory, get_settings, sqlalchemy, or sqlmodel, and that no component imports
  request or application state.
- 275 passed, 4 skipped. ruff check clean.

Findings: HIGH-07, LOW-05

Co-authored-by: Copilot App <[email protected]>

tests/test_ui_boundaries.py

@@ -0,0 +1,85 @@
+"""Structural rules for the NiceGUI page layer.
+
+`.github/instructions/ui.instructions.md:23,31` forbids pages from owning
+persistence or query-building concerns, and forbids components from resolving
+request or application state. HIGH-07 recorded three violations of those rules;
+these tests keep them from coming back.
+"""
+
+from __future__ import annotations
+
+import ast
+from pathlib import Path
+
+UI_DIR = Path(__file__).resolve().parents[1] / "src" / "transcription" / "ui"
+PAGES_DIR = UI_DIR / "pages"
+COMPONENTS_DIR = UI_DIR / "components"
+
+# Names a page must not pull in: they hand the page a session, a transaction, ORM
+# loader introspection, or process-global configuration.
+FORBIDDEN_PAGE_IMPORTS = frozenset(
+    {
+        "session_scope",
+        "transaction_scope",
+        "get_session_factory",
+        "resolve_session_factory",
+        "get_settings",
+        "get_engine",
+        "upgrade_schema",
+        "create_all",
+    }
+)
+
+FORBIDDEN_PAGE_MODULES = frozenset({"sqlalchemy", "sqlmodel"})
+
+
+def _page_paths() -> list[Path]:
+    return sorted(path for path in PAGES_DIR.glob("*.py") if path.stem != "__init__")
+
+
+def _component_paths() -> list[Path]:
+    return sorted(COMPONENTS_DIR.rglob("*.py"))
+
+
+def _imports(tree: ast.Module) -> tuple[set[str], set[str]]:
+    """Return (imported names, imported root modules)."""
+    names: set[str] = set()
+    modules: set[str] = set()
+    for node in ast.walk(tree):
+        if isinstance(node, ast.ImportFrom):
+            if node.module and node.level == 0:
+                modules.add(node.module.split(".")[0])
+            names.update(alias.name for alias in node.names)
+        elif isinstance(node, ast.Import):
+            for alias in node.names:
+                modules.add(alias.name.split(".")[0])
+                names.add(alias.name)
+    return names, modules
+
+
+def test_page_modules_are_discovered():
+    """Guard the guard: the rules below are meaningless if nothing is scanned."""
+    discovered = {path.stem for path in _page_paths()}
+    assert discovered >= {"documents_page", "jobs_page", "people_page", "sources_page"}
+
+
+def test_no_page_imports_persistence_or_process_globals():
+    """HIGH-07: pages orchestrate services; they do not own sessions or settings."""
+    violations: dict[str, list[str]] = {}
+    for path in _page_paths():
+        names, modules = _imports(ast.parse(path.read_text(encoding="utf-8")))
+        found = sorted((names & FORBIDDEN_PAGE_IMPORTS) | (modules & FORBIDDEN_PAGE_MODULES))
+        if found:
+            violations[path.stem] = found
+    assert violations == {}
+
+
+def test_no_component_resolves_request_or_application_state():
+    """`ui.instructions.md:31`: components render, they do not resolve app state."""
+    violations: dict[str, list[str]] = {}
+    for path in _component_paths():
+        names, modules = _imports(ast.parse(path.read_text(encoding="utf-8")))
+        found = sorted((names & FORBIDDEN_PAGE_IMPORTS) | (modules & (FORBIDDEN_PAGE_MODULES | {"fastapi"})))
+        if found:
+            violations[str(path.relative_to(COMPONENTS_DIR))] = found
+    assert violations == {}