docs(saved-filters,dashboard,system,series): Beam WO3 batch 5 — 15 endpoints + dedupe

Beam drafted 15 frontmatter'd docs (saved-filters CRUD, dashboard
sections/preferences/restore, system config/settings, series list + books);
Claude verified shapes against handlers and pinned the registry:
- saved-filters: SavedFilterResponse pinned by type (RFC3339 timestamps here,
  unlike most of the API); create/update share CreateSavedFilterRequest
  (resource_type oneof media-items|collections|devices)
- dashboard: preferences GET pin {hidden_collections, collection_order,
  items_per_section}; PUT returns full UserDashboardPreferences row; sections
  wrapper {sections}
- system: GET+PUT /api/system/config are admin-defined key/value maps — new
  AnyJSONObject sentinel (gate shape-checks without key comparison; request
  side too). UpdateSystemConfiguration returns {status, message} — verified,
  not guessed. GET /api/system/settings returns []SettingEntry.
- series: {series[{name, library_id, book_count, total_in_series,
  cover_paths, last_entry_at}], total, limit, offset}; books by
  ?name=&library_id= with family-lens 403

Dedupe: deleted dashboard.md, system/config.md, system/settings.md — each
covered the same endpoints as Beam's per-endpoint files (content merged by
the gate-verified shapes; old prose recoverable from git).

Beam clarifications confirmed: scanner routes are WO5 (docs exist);
progress/books-match are WO5.

internal/docs/schema.go

@@ -34,6 +34,10 @@ type Schema struct {
 	Response any
 }
 
+// AnyJSONObject marks responses whose keys are dynamic (admin-defined config
+// maps etc.): the gate then only verifies the example is a JSON object.
+type AnyJSONObject struct{}
+
 // Schemas is keyed by "METHOD path" in Echo syntax. Sample values inside
 // RawMessage pins use empty strings / zero values — only the KEY SET is
 // checked, never the values.
@@ -254,4 +258,70 @@ var Schemas = map[string]Schema{
 	"GET /api/jobs/:jobId": {
 		Response: services.JobResult{},
 	},
+
+	// --- WO3 tail batch: saved-filters, dashboard, system, series ---
+	"GET /api/saved-filters": {
+		Response: []handlers.SavedFilterResponse{},
+	},
+	"GET /api/saved-filters/:id": {
+		Response: handlers.SavedFilterResponse{},
+	},
+	"POST /api/saved-filters": {
+		Request:  handlers.CreateSavedFilterRequest{},
+		Response: handlers.SavedFilterResponse{},
+	},
+	"PUT /api/saved-filters/:id": {
+		Request:  handlers.CreateSavedFilterRequest{}, // same struct reused for update
+		Response: handlers.SavedFilterResponse{},
+	},
+	"DELETE /api/saved-filters/:id": {},
+	"GET /api/dashboard/sections": {
+		Response: json.RawMessage(`{"sections": []}`),
+	},
+	"GET /api/dashboard/preferences": {
+		Response: json.RawMessage(`{
+			"hidden_collections": [], "collection_order": [],
+			"items_per_section": 0
+		}`),
+	},
+	"PUT /api/dashboard/preferences": {
+		Request: json.RawMessage(`{
+			"library_id": null, "hidden_collections": [],
+			"collection_order": [], "items_per_section": 0
+		}`),
+		Response: database.UserDashboardPreferences{},
+	},
+	"POST /api/dashboard/restore-system-collection": {
+		Request:  json.RawMessage(`{"collection_name": "", "reset_type": ""}`),
+		Response: json.RawMessage(`{"message": ""}`),
+	},
+	"GET /api/system/config": {
+		// Admin-defined key/value map — arbitrary keys.
+		Response: AnyJSONObject{},
+	},
+	"PUT /api/system/config": {
+		Request:  AnyJSONObject{}, // map[string]string of key -> new value
+		Response: json.RawMessage(`{"status": "", "message": ""}`),
+	},
+	"GET /api/system/settings": {
+		Response: []database.SettingEntry{},
+	},
+	"PUT /api/system/settings": {
+		Request:  handlers.UpdateSettingRequest{},
+		Response: handlers.UpdateSettingResponse{},
+	},
+	"GET /api/series": {
+		Response: json.RawMessage(`{
+			"series": [{
+				"name": "", "library_id": "", "book_count": 0,
+				"total_in_series": 0, "cover_paths": [], "last_entry_at": ""
+			}],
+			"total": 0, "limit": 0, "offset": 0
+		}`),
+	},
+	"GET /api/series/books": {
+		Response: json.RawMessage(`{
+			"name": "", "library_id": "", "books": [], "total": 0
+		}`),
+	},
 }