chore: delete dead progress handlers, no-op scar, split fused helper line

Batch H1 step 4:
- Handler GetUniversalProgress (progress.go) deleted — no route mounts
  it; only /api/progress/:id/history (GetProgressHistory) and the SSR
  /progress page exist. Note: the bruno universal-progress suite
  documents GET/PUT /api/progress/:id + /api/progress/device/:device_id
  — those routes do NOT exist server-side; that suite is stale
  documentation, flagged in the plan.
- Handler GetAllProgress deleted — unregistered near-copy of
  GetAllProgressData (which the /progress SSR page uses and stays).
- series.go: dropped the `_ = libTypes` no-op (libTypes IS used by the
  Badge line right below — the assignment stays).
- router/helpers.go: visibleLibraryIDsFor's signature and first
  statement were fused onto one line; split for readability. No
  behavior change.

internal/router/helpers.go

@@ -252,7 +252,8 @@ func resolveLibrary(c *echo.Context, cfg *Config, userUUID string) LibraryResolu
 
 // visibleLibraryIDsFor returns the requester's visible-library id set (for
 // membership checks) plus the ids themselves (for SQL ANY() filters).
-func visibleLibraryIDsFor(c *echo.Context, cfg *Config) (map[string]bool, []pgtype.UUID, error) {	userUUIDStr, ok := c.Get("user_id").(string)
+func visibleLibraryIDsFor(c *echo.Context, cfg *Config) (map[string]bool, []pgtype.UUID, error) {
+	userUUIDStr, ok := c.Get("user_id").(string)
 	if !ok {
 		return nil, nil, echo.NewHTTPError(http.StatusUnauthorized, "invalid user")
 	}