docs: UI-audit fixes in CLAUDE.md, API, OpenAPI, LANES and READMEs

New params and errors (agents session_ids, sessions awaiting/from/to,
stats tool counts, event labels, cleanup dry_run/INVALID_PURGE_DAYS, lane
start slot auto/ESESSIONLIVE/EUNSUPPORTED), terminal and pane shortcuts,
the shared UI primitives, accent vs accent-solid, lazy routes and the
Settings groups. openapi.yaml regenerated.

server/openapi-extra/override-ops.js

@@ -1205,7 +1205,7 @@ const paths = {
       tags: ["Settings"],
       summary: "Abandon stale sessions and optionally purge old history",
       description:
-        "Two-phase maintenance. Phase 1 (`abandon_hours`, non-destructive): marks any still-`active` session with no events newer than that many hours as `abandoned`, and completes its lingering agents — a tidy-up of crashed/orphaned sessions. Phase 2 (`purge_days`) is ⚠ DESTRUCTIVE and IRREVERSIBLE: it permanently DELETES completed/error/abandoned sessions (and their events, agents, and token_usage) whose `started_at` is older than that many days. Active sessions are NEVER purged. Both fields are optional and independent — send only `abandon_hours` for a safe tidy-up, or include `purge_days` to also reclaim disk. Export first if the purged history matters. The response reports counts for each phase.",
+        "Two-phase maintenance. Phase 1 (`abandon_hours`, non-destructive): marks any still-`active` session with no events newer than that many hours as `abandoned`, and completes its lingering agents — a tidy-up of crashed/orphaned sessions. Phase 2 (`purge_days`) is ⚠ DESTRUCTIVE and IRREVERSIBLE: it permanently DELETES completed/error/abandoned sessions (and their events, agents, and token_usage) whose `started_at` is older than that many days. Active sessions are NEVER purged. Both fields are optional and independent — send only `abandon_hours` for a safe tidy-up, or include `purge_days` to also reclaim disk. Export first if the purged history matters. `purge_days` must be a whole number ≥ 1, else 400 `INVALID_PURGE_DAYS` (a fraction like 0.1 would purge almost everything). `dry_run: true` answers the same counts (plus `dry_run: true`) and changes nothing — preview a purge before running it. The response reports counts for each phase.",
       operationId: "cleanupData",
       requestBody: {
         required: true,
@@ -1222,6 +1222,10 @@ const paths = {
                   "Abandon stale sessions, then purge history older than 90 days (destructive)",
                 value: { abandon_hours: 12, purge_days: 90 },
               },
+              preview: {
+                summary: "Dry run: count what a 90-day purge would delete, change nothing",
+                value: { purge_days: 90, dry_run: true },
+              },
             },
           },
         },
@@ -1236,6 +1240,20 @@ const paths = {
             },
           },
         },
+        400: {
+          description: "purge_days is not a whole number of days, 1 or more",
+          content: {
+            "application/json": {
+              schema: { $ref: "#/components/schemas/ErrorResponse" },
+              example: {
+                error: {
+                  code: "INVALID_PURGE_DAYS",
+                  message: "purge_days must be a whole number of days, 1 or more",
+                },
+              },
+            },
+          },
+        },
       },
     },
   },