docs(libraries): Work Order 3 batch 2 — 10 missing endpoints + array-response gate support

New frontmatter'd docs with handler-compatible shapes:
- get_library_types.md (public; []LibraryTypes)
- list_libraries.md (admin; {data: ListLibrariesRow})
- get_library_folders.md (admin; []LibraryFolders)
- list/get stats/resolve/delete processing issues (admin; family-lens 403s
  documented)
- scan_library.md (202 + 409 coalescing with active_job_id)
- get/update scan-settings (ScanSettingsResponse)

Gate improvements forced by this batch:
- Array responses: registered slice -> doc example must be a JSON array; key
  set compared against the element type
- RawMessage pins may now be arrays
- update scan-settings uses a RawMessage pin: handler always sets Message but
  the struct's omitempty would reject correct docs via zero-value marshal

Registry: sqlc models pinned directly (LibraryTypes, LibraryFolders,
ListLibrariesRow — json tags verified in the generated code).

internal/docs/schema.go

@@ -3,6 +3,7 @@ package docs
 import (
 	"encoding/json"
 
+	"bookhoard/internal/database"
 	"bookhoard/internal/handlers"
 	"bookhoard/internal/services"
 )
@@ -89,9 +90,9 @@ var Schemas = map[string]Schema{
 	},
 	"GET /api/devices/:id/collections": {
 		Response: struct {
-			DeviceID string                                 `json:"device_id"`
-			Mappings []handlers.DeviceMappingSummary        `json:"mappings"`
-			Total    int                                    `json:"total"`
+			DeviceID string                          `json:"device_id"`
+			Mappings []handlers.DeviceMappingSummary `json:"mappings"`
+			Total    int                             `json:"total"`
 		}{},
 	},
 	"PUT /api/devices/:id/collections/:collectionId": {
@@ -119,4 +120,47 @@ var Schemas = map[string]Schema{
 			}
 		}`),
 	},
+
+	// --- libraries (batch 2) ---
+	"GET /api/libraries/types": {
+		Response: []database.LibraryTypes{},
+	},
+	"GET /api/libraries": {
+		Response: struct {
+			Data []database.ListLibrariesRow `json:"data"`
+		}{},
+	},
+	"GET /api/libraries/:id/folders": {
+		Response: []database.LibraryFolders{},
+	},
+	"GET /api/libraries/:id/issues/list": {
+		Response: []handlers.ProcessingIssueResponse{},
+	},
+	"GET /api/libraries/:id/issues/stats": {
+		Response: handlers.ProcessingIssueStats{},
+	},
+	"POST /api/libraries/:id/issues/:issueId/:mediaItemId/resolve": {
+		Response: json.RawMessage(`{"success": false, "message": ""}`),
+	},
+	"DELETE /api/libraries/:id/issues/:issueId": {
+		Response: json.RawMessage(`{"success": false, "message": ""}`),
+	},
+	"POST /api/libraries/:id/scan": {
+		Request:  nil, // library_id injected from the path; no body used
+		Response: json.RawMessage(`{"message": "", "job_id": "", "status": ""}`),
+	},
+	"GET /api/libraries/scan-settings": {
+		Response: handlers.ScanSettingsResponse{},
+	},
+	"PUT /api/libraries/scan-settings": {
+		Request: handlers.UpdateScanSettingsRequest{},
+		// RawMessage pin (not the struct): the update handler ALWAYS sets
+		// Message, but the struct's omitempty would drop it from a
+		// zero-value marshal and the gate would reject correct docs.
+		Response: json.RawMessage(`{
+			"scan_poll_interval_seconds": 0,
+			"auto_scan_enabled": false,
+			"message": ""
+		}`),
+	},
 }