Show all open (unactioned) items by default, not just the last scan

The default results view loaded only the latest scan session (±300s
window), so items dropped out of sight once a newer scan started — and
a long scheduled scan could show little or nothing on browser open.

Add get_open_items(): every flagged item with no disposition (or status
'unreviewed') across all scans, deduped by id to the latest finished
scan. GET /api/db/flagged now serves it when no ?ref is given; ?ref=N
still loads a specific past session. Frontend loadHistorySession(null)
routes to a new loadOpenItems() loader. Rename the banner button to
"Open items" (da/de/en).

get_session_items() default is unchanged — export.py and
scan_scheduler.py still rely on latest-session for the current scan's
report/email.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

static/js/CLAUDE.md

@@ -40,7 +40,8 @@ Never revert to `!!window._googleConnected` / `_fileSources.length > 0` — thos
 
 ## Scan history browser — history.js + results.js
 
-- **`S._historyRefScanId`** — `null` = live/SSE mode; positive int = viewing a past session. Set by `loadHistorySession()`; cleared by `exitHistoryMode()`.
+- **`S._historyRefScanId`** — `null` = live/SSE mode **or** the default open-items view; positive int = viewing a past session. Set by `loadHistorySession()`; cleared by `exitHistoryMode()`.
+- **`loadHistorySession(null)` → `loadOpenItems()`** — passing `null` no longer resolves to the latest session. It now loads **all open (unactioned) items across every scan** via `GET /api/db/flagged` (no `ref`), leaves `_historyRefScanId` null, and shows no history banner. The "Open items" banner button (`onclick="loadHistorySession(null)"`, key `history_btn_latest`) therefore returns to this open-items view. Specific sessions are still loaded with a positive `ref`, which keeps the re-scan resolved-diff. Do not revert `null` to "resolve latest ref" — that reintroduces the "only the last scan is shown" complaint.
 - **Auto-load on page load** — `_sseWatchdog()` in `results.js` calls `window.loadHistorySession?.(null)` whenever `/api/scan/status` reports neither `running` (M365 + file lock) nor `google_running` (Google lock) **and** nothing is shown yet (`!S._historyRefScanId && !S.flaggedData.length`). This is **not one-shot** — it retries on every 4s poll until a session is restored, because (a) the replay buffer is empty after a server restart so `sse_replay_done` never fires, and (b) a completed scan's replayed `scan_phase` can leave a running flag set that would otherwise block the load forever. Because both locks are confirmed free, the watchdog clears the stale `_m365/_google/_fileScanRunning` flags before calling. Do not revert to a one-shot `_initialStatusChecked` gate — that reintroduces the "blank grid after refresh/restart" bug. `/api/scan/status` **must** report `google_running` separately; `running` alone misses live Google scans. The `sse_replay_done` handler in `scan.js` still retries for the non-empty-buffer (no-restart) case.
 - **History banner** (`#historyBanner`) — shown when `S._historyRefScanId` is set. Do not hide/show from outside `history.js`.
 - **Session picker** (`#historyDropdown`) — rendered inside `[data-history-wrap]` so the outside-click handler works correctly. Do not move the picker outside this wrapper.