overview: one endpoint, live projections and a response cache (m36)

docs/reference/api.md

@@ -109,11 +109,7 @@ Auth `open` means no session is required; `session` means a valid session cookie
 | GET | `/api/queries` | session | counted | read | Query log rows for the Activity page |
 | GET | `/api/queries/{id}` | session | counted | read | One query, fully explained |
 | GET | `/api/queries/live` | session | exempt | read | Live query stream (server-sent events) |
-| GET | `/api/stats` | session | counted | read | Totals for a period |
-| GET | `/api/stats/timeseries` | session | counted | read | Bucketed counts for a period |
-| GET | `/api/stats/types` | session | counted | read | Query-type breakdown for a period |
-| GET | `/api/stats/routes` | session | counted | read | How the period's queries were answered |
-| GET | `/api/stats/clients` | session | counted | read | Per-client bucketed counts for a period |
+| GET | `/api/overview` | session | counted | read | Everything the Overview page draws, for one period |
 | GET | `/api/lookup` | session | counted | read | Explain a domain |
 | GET | `/api/diagnostics` | session | counted | read | Operational event log |
 | DELETE | `/api/diagnostics` | session | counted | runtime action | Purge every resolved event |
@@ -221,6 +217,6 @@ A non-empty `rewrites.cname_target` on a query detail means the decision landed
 
 ### Coverage
 
-Every window-bounded read — `GET /api/queries` and the five `GET /api/stats*` endpoints — answers with a `coverage` object: `available_since` is the oldest instant the query log is still complete for, and `complete` is true only when the window the request asked about starts at or after it. Retention deletes rows and advances the watermark in one transaction, so a client can tell an empty window from a pruned one instead of charting the gap as zero. A request with no lower bound at all asks about the whole of history, and is never complete.
+Every window-bounded read — `GET /api/queries` and `GET /api/overview` — answers with a `coverage` object: `available_since` is the oldest instant the query log is still complete for, and `complete` is true only when the window the request asked about starts at or after it. Retention deletes rows and advances the watermark in one transaction, so a client can tell an empty window from a pruned one instead of charting the gap as zero. A request with no lower bound at all asks about the whole of history, and is never complete.
 
-Each of these responses reads its rows and its watermark inside one SQLite read transaction, so retention cannot prune between the two and hand back pre-prune rows tagged with a post-prune `available_since`. Coherence stops there: two separate requests are two separate reads, and queries logged between them can move the counts.
+Each of these responses reads its rows and its watermark inside one SQLite read transaction, so retention cannot prune between the two and hand back pre-prune rows tagged with a post-prune `available_since`. `GET /api/overview` puts every Overview panel inside that one transaction, so its totals and its four breakdowns describe one database state. Coherence stops there: two separate requests are two separate reads, and queries logged between them can move the counts.