feat(server/m7-381): admin scan-status + manual trigger endpoints

Adds GET /api/admin/scan/status and POST /api/admin/scan/run under the
existing RequireAdmin middleware block; plumbs *library.Scanner and
library.RunScanConfig through api.Mount, server.New, and main.go so the
manual trigger reuses the same RunScan orchestrator as startup scans.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/api/api.go

@@ -14,6 +14,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/coverart"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrquarantine"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrrequests"
@@ -25,7 +26,7 @@ import (
 // Mount attaches /api/* handlers to r. Public endpoints (login) are outside
 // RequireUser; everything else is gated by the middleware. The events writer
 // is shared with the Subsonic mount so /rest/scrobble feeds the same store.
-func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playevents.Writer, recCfg config.RecommendationConfig, lidarrCfg *lidarrconfig.Service, lidarrReqs *lidarrrequests.Service, lidarrQuar *lidarrquarantine.Service, tracksSvc *tracks.Service, playlistsSvc *playlists.Service, coverEnricher *coverart.Enricher, coverBackfillCap int, dataDir string) {
+func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playevents.Writer, recCfg config.RecommendationConfig, lidarrCfg *lidarrconfig.Service, lidarrReqs *lidarrrequests.Service, lidarrQuar *lidarrquarantine.Service, tracksSvc *tracks.Service, playlistsSvc *playlists.Service, coverEnricher *coverart.Enricher, coverBackfillCap int, scanner *library.Scanner, scanCfg library.RunScanConfig, dataDir string) {
 	rng := rand.New(rand.NewSource(rand.Int63()))
 	h := &handlers{
 		pool: pool, logger: logger, events: events, recCfg: recCfg,
@@ -37,6 +38,8 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
 		playlists:           playlistsSvc,
 		coverart:            coverEnricher,
 		coverArtBackfillCap: coverBackfillCap,
+		scanner:             scanner,
+		scanCfg:             scanCfg,
 		dataDir:             dataDir,
 	}
 
@@ -108,6 +111,9 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
 
 				admin.Post("/albums/{id}/cover/refetch", h.handleAdminAlbumRefetchCover)
 				admin.Post("/covers/refetch-missing", h.handleAdminBulkRefetchCovers)
+
+				admin.Get("/scan/status", h.handleGetScanStatus)
+				admin.Post("/scan/run", h.handleTriggerScan)
 			})
 
 			authed.Get("/playlists", h.handleListPlaylists)
@@ -136,5 +142,7 @@ type handlers struct {
 	playlists           *playlists.Service
 	coverart            *coverart.Enricher
 	coverArtBackfillCap int
+	scanner             *library.Scanner
+	scanCfg             library.RunScanConfig
 	dataDir             string
 }